Tagged Coronavirus Risks and Safety Concerns

Has the Era of Overzealous Cleaning Finally Come to an End?

This week, the C.D.C. acknowledged what scientists have been saying for months: The risk of catching the coronavirus from surfaces is low.

When the coronavirus began to spread in the United States last spring, many experts warned of the danger posed by surfaces. Researchers reported that the virus could survive for days on plastic or stainless steel, and the Centers for Disease Control and Prevention advised that if someone touched one of these contaminated surfaces — and then touched their eyes, nose or mouth — they could become infected.

Americans responded in kind, wiping down groceries, quarantining mail and clearing drugstore shelves of Clorox wipes. Facebook closed two of its offices for a “deep cleaning.” New York’s Metropolitan Transportation Authority began disinfecting subway cars every night.

But the era of “hygiene theater” may have come to an unofficial end this week, when the C.D.C. updated its surface cleaning guidelines and noted that the risk of contracting the virus from touching a contaminated surface was less than 1 in 10,000.

“People can be affected with the virus that causes Covid-19 through contact with contaminated surfaces and objects,” Dr. Rochelle Walensky, the director of the C.D.C., said at a White House briefing on Monday. “However, evidence has demonstrated that the risk by this route of infection of transmission is actually low.”

The admission is long overdue, scientists say.

“Finally,” said Linsey Marr, an expert on airborne viruses at Virginia Tech. “We’ve known this for a long time and yet people are still focusing so much on surface cleaning.” She added, “There’s really no evidence that anyone has ever gotten Covid-19 by touching a contaminated surface.”

During the early days of the pandemic, many experts believed that the virus spread primarily through large respiratory droplets. These droplets are too heavy to travel long distances through the air but can fall onto objects and surfaces.

In this context, a focus on scrubbing down every surface seemed to make sense. “Surface cleaning is more familiar,” Dr. Marr said. “We know how to do it. You can see people doing it, you see the clean surface. And so I think it makes people feel safer.”

A “sanitization specialist” at an Applebee’s Grill and Bar in Westbury, N.Y., wiping down a used pen last year. Restaurants and other businesses have highlighted extra cleaning in their marketing since the pandemic began.
A “sanitization specialist” at an Applebee’s Grill and Bar in Westbury, N.Y., wiping down a used pen last year. Restaurants and other businesses have highlighted extra cleaning in their marketing since the pandemic began.Hiroko Masuike/The New York Times

But over the last year, it has become increasingly clear that the virus spreads primarily through the air — in both large and small droplets, which can remain aloft longer — and that scouring door handles and subway seats does little to keep people safe.

“The scientific basis for all this concern about surfaces is very slim — slim to none,” said Emanuel Goldman, a microbiologist at Rutgers University, who wrote last summer that the risk of surface transmission had been overblown. “This is a virus you get by breathing. It’s not a virus you get by touching.”

The C.D.C. has previously acknowledged that surfaces are not the primary way that the virus spreads. But the agency’s statements this week went farther.

“The most important part of this update is that they’re clearly communicating to the public the correct, low risk from surfaces, which is not a message that has been clearly communicated for the past year,” said Joseph Allen, a building safety expert at the Harvard T.H. Chan School of Public Health.

Catching the virus from surfaces remains theoretically possible, he noted. But it requires many things to go wrong: a lot of fresh, infectious viral particles to be deposited on a surface, and then for a relatively large quantity of them to be quickly transferred to someone’s hand and then to their face. “Presence on a surface does not equal risk,” Dr. Allen said.

In most cases, cleaning with simple soap and water — in addition to hand-washing and mask-wearing — is enough to keep the odds of surface transmission low, the C.D.C.’s updated cleaning guidelines say. In most everyday scenarios and environments, people do not need to use chemical disinfectants, the agency notes.

“What this does very usefully, I think, is tell us what we don’t need to do,” said Donald Milton, an aerosol scientist at the University of Maryland. “Doing a lot of spraying and misting of chemicals isn’t helpful.”

Still, the guidelines do suggest that if someone who has Covid-19 has been in a particular space within the last day, the area should be both cleaned and disinfected.

“Disinfection is only recommended in indoor settings — schools and homes — where there has been a suspected or confirmed case of Covid-19 within the last 24 hours,” Dr. Walensky said during the White House briefing. “Also, in most cases, fogging, fumigation and wide-area or electrostatic spraying is not recommended as a primary method of disinfection and has several safety risks to consider.”

And the new cleaning guidelines do not apply to health care facilities, which may require more intensive cleaning and disinfection.

Saskia Popescu, an infectious disease epidemiologist at George Mason University, said that she was happy to see the new guidance, which “reflects our evolving data on transmission throughout the pandemic.”

But she noted that it remained important to continue doing some regular cleaning — and maintaining good hand-washing practices — to reduce the risk of contracting not just the coronavirus but any other pathogens that might be lingering on a particular surface.

Dr. Allen said that the school and business officials he has spoken with this week expressed relief over the updated guidelines, which will allow them to pull back on some of their intensive cleaning regimens. “This frees up a lot of organizations to spend that money better,” he said.

Schools, businesses and other institutions that want to keep people safe should shift their attention from surfaces to air quality, he said, and invest in improved ventilation and filtration.

“This should be the end of deep cleaning,” Dr. Allen said, noting that the misplaced focus on surfaces has had real costs. “It has led to closed playgrounds, it has led to taking nets off basketball courts, it has led to quarantining books in the library. It has led to entire missed school days for deep cleaning. It has led to not being able to share a pencil. So that’s all that hygiene theater, and it’s a direct result of not properly classifying surface transmission as low risk.”

Roni Caryn Rabin contributed reporting

Covid-19 Vaccine Side Effects: Your Questions Answered

The most common questions about vaccination side effects, answered.

Every day nearly three million people in the United States are getting the Covid-19 vaccine. And every new jab prompts new questions about what to expect after vaccination.

Last week I asked readers to send me their questions about vaccinations. Here are some answers.

Q: I’ve heard the Covid vaccine side effects, especially after the second dose, can be really bad. Should I be worried?

Short-lived side effects like fatigue, headache, muscle aches and fever are more common after the second dose of both the Pfizer-BioNTech and the Moderna vaccines, which each require two shots. (The Johnson & Johnson vaccine requires only a single shot.) Patients who experience unpleasant side effects after the second dose often describe feeling as if they have a bad flu and use phrases like “it flattened me” or “I was useless for two days.” During vaccine studies, patients were advised to schedule a few days off work after the second dose just in case they needed to spend a day or two in bed.

Data collected from v-safe, the app everyone is encouraged to use to track side effects after vaccination, also show an increase in reported side effects after the second dose. For instance, about 29 percent of people reported fatigue after the first Pfizer-BioNTech shot, but that jumped to 50 percent after the second dose. Muscle pain rose from 17 percent after the first shot to 42 percent after the second. While only about 7 percent of people got chills and fever after the first dose, that increased to about 26 percent after the second dose.

The New York Times interviewed several dozen of the newly vaccinated in the days afterward. They recounted a wide spectrum of responses, from no reaction at all to symptoms like uncontrolled shivering and “brain fog.” While these experiences aren’t pleasant, they are a sign that your own immune system is mounting a potent response to the vaccine.

Q: Is it true that women are more likely to get worse side effects from the vaccine than men?

An analysis of safety data from the first 13.7 million Covid-19 vaccine doses given to Americans found that side effects were more common in women. And while severe reactions to the Covid vaccine are rare, nearly all the cases of anaphylaxis, or life-threatening allergic reactions, occurred in women.

The finding that women are more likely to report and experience unpleasant side effects to the Covid vaccine is consistent with other vaccines as well. Women and girls can produce up to twice as many antibodies after receiving flu shots and vaccines for measles, mumps and rubella (M.M.R.) and hepatitis A and B. One study found that over nearly three decades, women accounted for 80 percent of all adult anaphylactic reactions to vaccines.

While it’s true that women may be more likely to report side effects than men, the higher rate of side effects in women also has a biological explanation. Estrogen can stimulate an immune response, whereas testosterone can blunt it. In addition, many immune-related genes are on the X chromosome, of which women have two copies and men have only one. These robust immune responses help to explain why 80 percent of autoimmune diseases afflict women. You can read more about women and vaccine side effects here.

Q: I didn’t have any side effects. Does that mean my immune system didn’t respond and the vaccine isn’t working?

Side effects get all the attention, but if you look at the data from vaccine clinical trials and the real world, you’ll see that many people don’t experience any side effects beyond a sore arm. In the Pfizer vaccine trials, about one out of four patients reported no side effects. In the Moderna trials, 57 percent of patients (64 or younger) reported side effects after the first dose — that jumped to 82 percent after the second dose, which means almost one in five patients reported no reaction after the second shot.

A lack of side effects does not mean the vaccine isn’t working, said Dr. Paul Offit, a professor at the University of Pennsylvania and a member of the Food and Drug Administration’s vaccine advisory panel. Dr. Offit noted that during the vaccine trials, a significant number of people didn’t report side effects, and yet the trials showed that about 95 percent of people were protected. “That proves you don’t have to have side effects in order to be protected,” he said.

Nobody really knows why some people have a lot of side effects and others have none. We do know that younger people mount stronger immune responses to vaccines than older people, whose immune systems get weaker with age. Women typically have stronger immune responses than men. But again, these differences don’t mean that you aren’t protected if you don’t feel much after getting the shot.

Scientists still aren’t sure how effective the vaccines are in people whose immune systems may be weakened from certain medical conditions, such as cancer treatments or H.I.V. infection or because they are taking immune suppressing drugs. But most experts believe the vaccines still offer these patients some protection against Covid-19.

The bottom line is that even though individual immune responses can vary, the data collected so far show that all three vaccines approved in the United States — Pfizer-BioNTech, Moderna and Johnson & Johnson — are effective against severe illness and death from Covid-19.

Q: I took Tylenol before I had my Covid vaccine shots and had very little reaction to the shots. Did I make a big mistake?

You shouldn’t try to stave off discomfort by taking a pain reliever before getting the shot. The concern is that premedicating with a pain reliever like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin), which can prevent side effects like arm soreness as well as fever or headache, might also blunt your body’s immune response.

While it’s possible that taking a pain reliever before your shots might have dampened your body’s immune response, vaccine experts say you shouldn’t worry, and you shouldn’t try to get another shot. Studies of other vaccines suggest that while premedicating can dull the body’s immune response to a vaccine, your immune system can still mount a strong enough defense to fight infection. A review of studies of more than 5,000 children compared antibody levels in children who took pain relievers before and after vaccinations and those who did not. They found that pain relievers did not have a meaningful impact on immune response, and that children in both groups generated adequate levels of antibodies after their shots.

The high efficacy of all the Covid vaccines suggests that even if taking Tylenol before the shot did blunt your body’s immune response, there’s some wiggle room, and you are likely still well protected against Covid-19. “You should feel reassured that you’ll have enough of an immune response that you’ll will be protected, especially for vaccines that are this good,” said Dr. Offit.

Q: What about taking a pain reliever after the shot?

“It’s OK to treat” side effects with a pain reliever, said Dr. Offit, but if you don’t really need one, “don’t take it.”

While most experts agree it’s safe to take a pain reliever to relieve discomfort after you get vaccinated, they advise against taking it after the shot as a preventive or if your symptoms are manageable without it. The concern with taking an unnecessary pain reliever is that it could blunt some of the effects of the vaccine. (In terms of the vaccine, there’s no meaningful difference if you choose acetaminophen or ibuprofen.)

During the Moderna trial, about 26 percent of people took acetaminophen to relieve side effects, and the overall efficacy of the vaccine still was 94 percent.

Q: Are the side effects worse if you’ve already had Covid-19?

Research and anecdotal reports suggest that people with a previously diagnosed Covid-19 infection may have a stronger reaction and more side effects after their first dose of vaccine compared to those who were never infected with the virus. A strong reaction to your first dose of vaccine also might be a sign that you were previously infected, even if you weren’t aware of it.

If you previously tested positive for Covid-19 or had a positive antibody blood test, be prepared for a stronger reaction to your first dose, and consider scheduling a few days off work just in case. Not only will it be more comfortable to stay home and recover in bed, the vaccine side effects can resemble the symptoms Covid-19, and your co-workers won’t want to be near you anyway.

Q: I had Covid-19 already. Does that mean I can just get one dose?

Studies suggest that one dose might be adequate for people who have a previously confirmed case of Covid-19, but so far the medical guidelines haven’t changed. If you’ve received the Pfizer-BioNTech or Moderna vaccines, you should plan to get your second dose even if you’ve had Covid-19. Skipping your second dose could create problems if your employer or an airline ask to see proof of vaccination in the future. If you live in an area where the single-dose Johnson & Johnson vaccine is available, then you can be fully vaccinated after just one dose. You can read more here about the vaccine response in people who’ve had Covid-19.

Q: Will the vaccines work against the new variants that have emerged around the world?

The vaccines appear to be effective against a new variant that originated in Britain and is quickly becoming dominant in the United States. But some variants of the coronavirus, particularly one first identified in South Africa and one in Brazil, appear to be more adept at dodging antibodies in vaccinated people.

While that sounds worrisome, there’s reason to be hopeful. Vaccinated people exposed to a more resistant variant still appear to be protected against serious illness. And scientists have a clear enough understanding of the variants that they already are working on developing booster shots that will target the variants. The variants identified in South Africa and Brazil are not yet widespread in the United States.

People who are vaccinated should still wear masks in public and comply with public health guidelines, but you shouldn’t live in fear of variants, said Dr. Peter J. Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston. “If you’re vaccinated, you should feel pretty confident about how protected you are,” said Dr. Hotez. “It’s unlikely you’ll ever go to a hospital or an I.C.U. with Covid-19. In time you’re going to see a recommendation for a booster.”

I hope these answers will reassure you about your own vaccine experience. You can find a more complete list of questions and answers in our special vaccine tool “Answers to All Your Questions About Getting Vaccinated Against Covid-19.”

What to Expect When You Get Your Covid Vaccine

What to Expect When You Get Your Covid Vaccine

Kevin Mohatt for The New York Times

With more Americans becoming eligible for vaccination, many have questions about what the experience is like.

Here, Times science and health reporters answer some frequently asked questions about vaccination →

Mar. 10, 2021
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Family Travel Gets Complicated Without a Covid Vaccine for Kids

Amid the chatter of travel’s long-awaited rebound one year into the pandemic, many families with children feel largely left out of the conversation.

Nearly every summer, Ada Ayala, a teacher, and her husband, Oscar Cesar Pleguezeulos, travel with their children to visit Mr. Cesar Pleguezeulos’s parents in Spain. But this year, even though they will both soon be fully vaccinated in their home state of Florida, they are changing their plans. The reason? There is still no pediatric Covid-19 vaccine available for their kids.

The travel industry, buoyed by news of vaccine rollouts, is anticipating a summer rush after a year of devastation. But amid the chatter of travel’s long-awaited rebound, many families with children — who comprise roughly 30 percent of the global travel market — say they are largely being left out of the conversation.

In a March survey on Bébé Voyage, an online community for traveling families, 90 percent of respondents said that amid unclear guidelines on Covid-19 testing, they were searching for flexible bookings. The topic also comes up often on Bébé Voyage’s Facebook page, particularly among parents in the United States. “It’s the Americans in the group that are the most nervous traveling with kids,” said the Bébé Voyage chief executive, Marianne Perez de Fransius.

Ms. Ayala, 44, is among those nervous parents. “If it wasn’t for the kids, we would definitely be flying this summer,” she said. Ms. Ayala already received her shot as a teacher. Her husband, also 44, will soon receive his shots, too, because Florida recently opened vaccinations to those age 40 and up. But their children, Charlise, 6, and Oscar, 2, will have to wait many more months to be inoculated.

“My 2-year-old isn’t going to wear a mask for 10 hours on a flight, and I don’t know if I want to expose him for a 16-hour trip with layovers,” Ms. Ayala said. “I’ll feel more confident when vaccination reaches more people worldwide, or at least in the destinations we want to go.”

Nearly one in three adults in the United States have now received at least one dose of the Covid-19 vaccine. But a full pediatric Covid-19 vaccine currently isn’t expected until the end of 2021 at the earliest, and while they wait, parents are struggling to figure out how they, too, can travel safely this summer, and even where their children are welcome as rules on quarantine and testing continue to shift.

“This is the elephant in the room right now,” said Cate Caruso, an adviser for Virtuoso, a network of luxury travel agencies, who also owns her own travel planning company, True Places Travel. The potential that a child could become infected with Covid-19 while abroad and not be allowed on a return flight, she said, is a major deterrent for parents. “Anywhere you go outside of the U.S. right now, you’ve got to think about how you’re going to get back in,” she said. “It’s leaving behind a whole bunch of people who are ready to go.”

In Ms. Ayala’s case, a compromise has been struck: If and when Spain — which is currently closed to American travelers — opens its borders, Mr. Cesar will travel to Spain with their daughter, Charlise, while Ms. Ayala will remain in Florida with Oscar. “She goes to school and is very good with wearing her mask, cleaning her hands and keeping distance,” Ms. Ayala said of her daughter. “So I think she can be safe. But it’s just not possible with a baby.”

But she doesn’t plan to stay home all summer. Whether or not her husband and daughter make it to Spain, Ms. Ayala is planning a family road trip at some point this summer, likely within Florida.

After a year of road trips, R.V.s and rental cottages, many Americans are now ready to fly again: Online searches for late-summer flights are up as much as 75 percent, and hotels on both coasts are reporting that they are sold out through October. But families, more than any other travel sector, continue to play it safe.

Family travel plans for this summer are more low-key than two years ago, with bookings to Mount Rushmore National Memorial, in the Black Hills of South Dakota, reported to be significantly up.
Family travel plans for this summer are more low-key than two years ago, with bookings to Mount Rushmore National Memorial, in the Black Hills of South Dakota, reported to be significantly up.Tannen Maury/EPA, via Shutterstock

Rovia, a membership-based global travel agency that works with both travelers and travel agents, reports that beach and camping destinations within driving distance are the most popular choices for families this summer. An exception? Disney World, which is seeing an uptick in reservations for summer from families looking to visit while capacity remains limited (and lines, as a result, remain shorter).

“The rate of couples traveling by air has increased faster, whereas families are still leaning toward travel by car and R.V. rentals,” said Jeff Gwynn, Rovia’s director of communications.

Montoya and Phil Hudson, who showcase their travels as a Black family on their popular blog, The Spring Break Family, are among them. “Most years we go pretty far — Spain, Italy, France, as far as we can go. This year it was about what’s reachable by car,” Ms. Hudson said. She and Mr. Hudson, who both work in the health care industry, are vaccinated, but admit they probably won’t be willing to fly with their two daughters, Leilah, 11, and Layla, 8, for several more months.

That’s because they want to wait for herd immunity to help keep their daughters safe. “The goal is to wait until the majority of the population is vaccinated, or has at least had the opportunity to become vaccinated,” Ms. Hudson said.

In addition to preferring driving over flying this summer, travel analysts say families with children will also continue to opt for rental homes over hotel rooms.

In fact, when it comes to the vacation cottage market, parents are booking faster than anyone else. “Families are the number one group expected to travel in 2021,” said Vered Schwarz, the president and chief operating officer of Guesty, a short-term property management platform which reports that its summer reservations are already 110 percent higher than 2020, with families comprising more than 30 percent of those booking. “For families with unvaccinated children, private rentals are appealing — they are comfortable and they avoid hotels chock-full of crowded common areas,” she said.

The question of how to treat unvaccinated children who may be traveling with their parents is also presenting a legal and ethical minefield for American travel operators.

The European Union is considering a vaccine passport that will allow free travel within the bloc for those who can show proof of inoculation. In Israel, a green pass has been established for those who have been vaccinated, granting holders not just the ability to cross a border but also check into a hotel or eat inside a restaurant, but children are not exempt — so parents with unvaccinated children must dine outside at restaurants and find babysitters before heading to the gym or a show.

But in the United States, such policies are unlikely to take hold, said Chuck Abbott, the general manager of the InterContinental San Diego. “Most hotels would not ask for that information, because it violates the privacy of the guest,” he said. “Even putting vaccinated guests on a different floor than other guests would likely present a legal issue.”

Compared with summer 2019, families’ plans for summer 2021 are more low-key: Travelocity reports that bookings to Mount Rushmore and Nashville are significantly up over two years ago; internationally, family bookings to London, Paris and Rome, destinations that were top family sites in 2019, but have still not reopened to U.S. travel, are way down, while Cancún, which is currently open to American travelers without quarantine requirements, is up nearly 50 percent.

Some European countries, like Iceland, have begun inching open their borders, but only to passengers who are vaccinated. That means individuals who can present proof of the Covid-19 jab can bypass quarantine when they arrive — unless they are parents traveling with children.

“Unvaccinated children would still need to quarantine for five days, and the parents, of course, must stay with the child,” said Eric Newman, who owns the travel blog Iceland With Kids. “Iceland’s brand-new travel regulations are not friendly to families hoping to visit with children.”

After a year of virtual schooling and working from home, parents have no desire to quarantine with their kids, said Anthony Berklich, the founder of the travel platform Inspired Citizen. “What these destinations are basically saying is you can come but your children can’t,” he said.

Instead, families are opting for warm-weather destinations closer to home.

When the Centers for Disease Control and Prevention announced in January that proof of a negative PCR test would be required of all air passengers arriving in the United States, many tropical resorts — including more than a dozen Hyatt properties — began offering not just free on-site testing, but a deeply discounted room in which to quarantine in case that test comes back positive. That move, said Rebecca Alesia, a travel consultant with SmartFlyer, has been a boon for family travel business.

“What happens if the morning you’re supposed to come home, you get up and Junior has a surprise positive test?” she said. “A lot of my clients have booked this summer because of this policy.”

For parents struggling to decide how and when to return to travel, there is good news on the horizon, said Dr. Shruti Gohil, the medical director of infection prevention at the University of California, Irvine.

“The chances of a good pediatric vaccine coming soon are high,” she said, noting that both Pfizer and Moderna are already running pediatric trials on their vaccines. “There is no reason to think that the vaccine will have any untoward effects on children that we haven’t already noted in adults.”

In the meantime, she said, parents with children need to continue to be cautious. That doesn’t mean families shouldn’t travel at all, but she recommends choosing to drive rather than fly; to not allow unvaccinated children to play unmasked with children from other households; and to remain vigilant about wearing masks and regularly washing hands while on the road.

“We can’t keep saying that you can’t go anywhere,” she said. “At some point we have to have some kind of nuance around this. But this is a game we are all still playing until the virus is gone.”

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Closing the Social Distance

After a year spent social distancing, mask wearing and sheltering in place, the prospect of readjusting to in-person social engagements can be a daunting one.

As the days grow warmer and vaccination shots reach more arms, you may be looking ahead to getting out and about. An Axios-Ipsos poll released this month found that “the number of Americans engaging in social interactions outside the home is increasing.” And the Centers for Disease Control and Prevention recently issued new recommendations that individuals who have been vaccinated against the coronavirus can start to gather in small groups, without masks, offering a measure of hope in particular to those who have missed the intimacy of double dates and dinner parties.

But after a year spent internalizing public health precautions for social distancing and mask-wearing, the prospect of readjusting to in-person social engagements may be a daunting one. For many, it provokes a sense of profound discomfort, apprehension or ambivalence.

“It’s a new version of anxiety,” said Dr. Lucy McBride, an internist in Washington who writes a newsletter about managing the coronavirus crisis. You may discover that your continuing concerns about the virus are colliding with a new set of worries about seeing others more regularly: What am I comfortable with? How do I act? What do I say?

“There’s two feelings that are continuing to exist for me,” said Allison Harris-Turk, 46, an events and communications consultant and mother of three in San Diego. Mrs. Harris-Turk created the Facebook group Learning in the Time of Corona, where many among the roughly 16,700 members are discussing the pros and cons of re-entry. “There’s the excitement and the optimism and the hope, and then there’s also the grief and the trauma and ‘oh, my goodness, how are we going to recover from this?’”

Here’s how some individuals and experts are starting to think about closing the social distance.

Start small.

Though you may be chafing at the confines of the lockdown, remember that it’s still not entirely safe to resume social activities as before. Across most of the country, the risk of coronavirus transmission remains high.

If you’re wary of re-entry, begin with a lower-stakes outing. “It’s like little baby steps getting back into it,” said Dr. David Hilden, a Minneapolis-based internist who hosts a weekly radio show during which he answers listeners’ pandemic questions. He’s observed this firsthand: Earlier this month, he met up with a friend to share a beer for the first time since the onset of the pandemic. “Now that we’ve dipped our toe in the water, a lot of Zoom meetings end with, ‘Hey, I think we can get together now,’” he said.

Understand that hanging out might take more effort.

After receiving her first shot of a coronavirus vaccine, Aditi Juneja, a New York-based lawyer, expected to feel the same flood of relief that some of her peers had described after getting theirs. While on the phone with a friend, she started to consider future late nights and travel to far-off destinations. “I was like, ‘Man, I want to dance on bars,’” Ms. Juneja, 30, said. “There was a euphoria about imagining the possibilities.”

But after 10 minutes, she found even the fantasy versions of these scenarios exhausting. The reality can be, too; she described the sensory overload and disorientation she felt while dining outdoors with a friend for the first time in months. “I think our ability to take inputs has really lowered,” Ms. Juneja said.

This is especially true for individuals suffering from social anxiety, for whom the lockdowns have offered some relief, and for whom reopening presents new stressors. But even extroverts may experience an adjustment period as our brains adapt to planning and monitoring responses to unfamiliar situations. At the beginning of the pandemic, people had to change their behaviors to comply with social distancing, mask-wearing and sheltering in place. But learning those new behaviors — and now, relearning old ones — can take a cognitive toll.

“Social settings are particularly demanding,” said David Badre, the author of the book “On Task: How Our Brain Gets Things Done” and a professor of cognitive, linguistic and psychological sciences at Brown University. “When we have to really focus and plan what we’re doing, that comes with an experience of mental effort,” he continued. “It feels like a mental fatigue.”

There is good news, however: You’ll most likely find it easier to relearn old behaviors than learn entirely new ones. “The key is to not avoid that effort,” Dr. Badre said. “By re-engaging, you will get used to it again.”

Set boundaries for yourself.

Though the past month has seen a spate of reopenings across the country, some scenarios might still set off a siren in your head. And because these facilities are open, doesn’t mean you need to go.

But what if a friend or family member does want to see a movie, or dine out? If you express disagreement over what is safe, you might feel as though you are implying your companions are less responsible or unethical.

Sunita Sah, a professor at University of Cambridge and Cornell University has researched this phenomenon, which she calls “insinuation anxiety.” In studies, Dr. Sah has found that patients frequently follow medical advice from their doctor even if they believe their doctor to have a conflict of interest, and that job candidates often answer interview questions they know are illegal to ask. These reactions come partly out of concern that to disagree would suggest the other person — the doctor or the job interviewer — is not trustworthy.

A similar situation can play out if you’re confronted with someone whose attitude toward public-health protocols differs from your own. Dr. Sah’s research has shown that when individuals have the opportunity to weigh their decisions in private, they are less likely to experience this anxiety and do something that makes them uncomfortable. She recommended writing down the boundaries that you would like to adhere to and taking time before agreeing to someone else’s plan.

“Assess your own risk level and comfort,” Dr. Sah said, “so you’re very clear about what you would and would not like to do.” This will also provide you with a clear document of how your comfort levels are changing over time as you readjust.

Brace for tough conversations.

Over the past year, public-health guidance often wildly varied on federal, state and even city levels, with some areas flinging open their doors while experts still advised caution. This has also been reflected in interpersonal relationships. It’s created friction between couples, families and friends, and prompted individuals to ask challenging, sometimes seemingly intrusive questions. Now, you may be adding “Are you vaccinated?” to that list. (On Twitter, one woman recently proposed “re-entry doulas” to help families navigate conversations about setting boundaries.)

Still, it will continue to be important to have these conversations in the coming months. “This isn’t abstract,” said Marci Gleason, an associate professor in the Department of Human Development and Family Sciences at the University of Texas at Austin whose lab has been surveying relationships in quarantine. “It comes directly to the question of whether we can socialize with others or not, in the way that they want to.” Sometimes, it can feel like a proxy battle over how much you value each other’s friendship. Be open about your own fears and vulnerabilities, and make it clear that when you disagree, you’re expressing your own preference and not rejecting the other person. Keep it simple, too, especially with friends or relatives with whom you don’t frequently have emotional, candid talks.

This empathy and candor will also be an asset if you find that your friends and peers have developed the tendency to over share, either out of anxiety or being starved for conversation. (You may be doing it yourself, too.) If a conversation subject makes you uncomfortable or anxious, say so.

“Being really open and direct is the best way,” said Dr. Danesh Alam, a psychiatrist and the medical director of behavior health services at Northwestern Medicine Central Dupage Hospital. Dr. Alam suggested studying up for conversations, preparing some questions and topics in order to chat with more intention and keep things on topic.

Take your time.

It’s OK if you don’t feel ready to see people socially again. Through the challenges of the lockdown period, you may have found that “your mental health is served best when you have time for calm and rest and introspection,” Dr. McBride said.

So pace yourself while considering the benefits of getting back out there: Even casual interactions have shown to foster a sense of belonging and community. “Social interaction is critical to our existence,” Dr. Alam said. Remember, too, that there are bound to be some weird moments as you start seeing others more regularly and your pandemic instincts (no hugging) and before-times instincts (“Do you want a bite of this?”) collide.

“If you’re comfortable going to a dinner at a small family restaurant, you can do that,” Dr. Hilden said. “If you want to wait a month or two, that’s OK, too.”

Teenagers, Anxiety Can Be Your Friend

Think of it as a personal warning system that will help you notice when things are on the wrong track.

For many teenagers, anxiety is riding high these days.

A new report from the University of Michigan’s C.S. Mott Children’s Hospital National Poll on Children’s Health found that one in three teen girls and one in five teen boys have experienced new or worsening anxiety since March 2020.

And a year into the pandemic, there’s certainly plenty to worry about. Maybe you’re feeling nervous about catching or spreading Covid-19, or about returning to in-person school. You might be feeling tense about where things stand with your friends or perhaps you’re on edge about something else altogether: your family, your schoolwork, your future, the health of the planet.

While I wish there were fewer reasons to be anxious right now, I do have good news for keeping yourself steady. Psychologists actually understand a lot about anxiety — both the mechanisms that drive it and interventions that get it under control — and what we know is quite reassuring. So if you’re looking to feel more at ease, start by letting go of these common myths.

Myth: I’d be better off if I never felt anxious.

Without question, anxiety feels bad — it’s no fun to have a pounding heart, sweaty palms and tightness in your chest — and for that reason, it’s easy to assume that it must be bad. But the discomfort of anxiety has a basic evolutionary function: to get us to tune into the fact that something’s not right.

You can think of anxiety as the emotional equivalent of the physical pain response. If you accidentally touch a hot burner, the pain makes you pull your hand away. In the same way, if your friends want to take a Covid-safe outdoor event and move it into a cramped indoor space, you should feel a surge of discomfort. That odd feeling in the pit of your stomach will help you to consider the situation carefully and be cautious about your next step.

Try to view anxiety as your own personal warning system. It’s more often a friend than a foe, one that will help you notice when things are on the wrong track.

Given this, when is anxiety unhelpful? While most of the anxiety you feel is likely to be healthy and protective, psychologists agree that anxiety becomes a problem if its alarm makes no sense — either going off for no reason or blaring when a chime would do.

In other words, you should not feel anxious when all is well, and when you do feel anxious, the intensity of your nerves should match the scale of the problem before you. Feeling a little tense before a big game is appropriate and may even improve your performance. Having a panic attack on the sidelines means your anxiety has gone too far. It may be worth talking to a mental health care provider for advice on how to manage it, but first you can try the proven techniques below.

Myth: There’s not much I can do about anxiety.

You do not need to feel helpless when your anxiety alarm goes off, and even when anxious feelings cross the line from healthy to unhealthy, there’s a lot you can do to settle your nerves. Keep in mind that anxiety has both physical and mental components. At the physical level, the amygdala, a primitive structure in the brain, detects a threat and sends the heart and lungs into overdrive getting your body ready to fight or flee that threat. This is helpful if you’re dealing with a problem that calls for attacking or running — you’re about to miss the school bus and need to break into a sprint to catch it — but bothersome if your one-note-Johnny amygdala gets your heart pounding and your lungs hyperventilating while you’re trying to take a test.

A really good way to curb the physical symptoms of anxiety? Controlled breathing. Though it can sound like a daffy approach to managing tension, breathing deeply and slowly activates a powerful part of the nervous system responsible for resetting the body to its pre-anxiety state. There are many good breathing techniques. Find one that you like. Practice it when you’re feeling calm. Put it to work when your amygdala overreacts.

For the mental component of anxiety, watch out for thoughts that are extremely negative. Are you thinking, “I’ll probably get sick if I go to school,” or “I’ll never find someone to sit with at lunch”? Such intense pessimism will almost certainly set you on edge. Counter your own catastrophic thoughts by asking yourself two questions: Am I overestimating the severity of the problem I’m facing? Am I underestimating my power to manage it? Weighing these questions will help you keep your concerns at healthy levels.

Myth: If something makes me anxious, I should avoid it.

Understandably, if we’re scared of something, we’re inclined to stay far away from it. Avoidance alleviates anxiety in the short term, but here’s the rub: In the long term, avoidance entrenches it. There are two separate factors at work here. The first is that it feels great when we steer clear of the things we dread. If you’ve been doing school remotely this year and get nervous when you picture your return to in-person learning, resolving to stay home will cause your worries to instantly drain away. It’s human nature to want to repeat any behavior that leads to feelings of pleasure or comfort, but every boost of avoidance-related relief increases the likelihood that you’ll want to continue to avoid what you fear.

The second factor in the avoidance-feeds-anxiety double whammy is that you rob yourself of the chance to find out that your worries are exaggerated. For example, the realities of in-person school are sure to be more manageable than the harrowing scenarios your imagination can create. Going to school would likely bring your worries down to size.

Facing our fears can reduce anxiety. But you don’t have to dive into nerve-racking experiences when wading in is an option. If social distancing has left you feeling unsure about the status of your friendships, you might be tempted to isolate yourself. Instead, come up with a small first step, such as making a plan to hang out with just one or two buddies before returning to the broader social scene. Get your feet wet and then take it from there.

With the world beginning to open up, it makes sense that you might feel nervous about easing back into it. Knowing what’s true about anxiety — and not — will make it easier to navigate the uncertain times ahead.


Why It Pays to Think Outside the Box on Coronavirus Tests

Universities and other institutions looking to protect themselves from Covid-19 may benefit from sharing their testing resources with the wider community, a new study suggests.

Last year, when the National Football League decided to stage its season in the midst of the coronavirus pandemic, it went all-in on testing. The league tested all players and personnel before they reported for summer training camp, and continued near-daily testing in the months that followed. Between Aug. 1 and the Super Bowl in early February, the N.F.L. administered almost one million tests to players and staff.

Many other organizations have sought safety in mass testing. The University of Illinois is testing its students, faculty and staff twice a week and has conducted more than 1.6 million tests since July. Major corporations, from Amazon to Tyson Foods, have rolled out extensive testing programs for their own employees.

Now, a new analysis suggests that schools, businesses and other organizations that want to keep themselves safe should think beyond strictly themselves. By dedicating a substantial proportion of their tests to people in the surrounding community, institutions could reduce the number of Covid-19 cases among their members by as much as 25 percent, researchers report in a new paper, which has not yet been published in a scientific journal.

“It’s natural in an outbreak for people to become self-serving, self-focused,” said Dr. Pardis Sabeti, a computational biologist at Harvard University and the Broad Institute who lead the analysis. But, she added, “If you’ve been in enough outbreaks you just understand that testing in a box doesn’t makes sense. These things are communicable, and they’re coming in from the community.”

The study has “really profound implications, especially if others can replicate it, said David O’Connor, a virologist at the University of Wisconsin, Madison, who was not involved in the analysis but reviewed a draft of the paper. As the pandemic enters its second year, he said, “We want to start using more sophisticated modeling and probably economic theory to inform what an optimal testing program would look like.”

Dr. Sabeti is an epidemic veteran, part of teams that responded to an Ebola outbreak in West Africa in 2014 and a mumps outbreak in the Boston area a few years later. When the coronavirus closed down the country last spring, many colleges and universities sought her advice on how to safely reopen.

At a time when testing resources were in short supply, many of these institutions were proposing intensive, expensive testing regimens focused entirely on their own members. Again and again, Dr. Sabeti suggested that universities think more broadly, and allocate some of their tests to people who might be friends, family members or neighbors of their students and employees.

“The metaphor I often used on the calls was to say, ‘You’re in a drought in a place with a lot of forest fires, and you have a shortage of fire alarms,’” she recalled. “‘And if you run out and buy every fire alarm and install it in your own house, you’ll be able to pick up a fire the moment it hits your house, but at that point it’s burning to the ground.’”

Still, convincing university officials to divert precious testing resources away from their own institutions was a hard sell, Dr. Sabeti said, especially without data on the effectiveness of the approach. So she and her colleagues decided to gather some.

“Fundamentally, the paper is about the intersection of kindness and success — how being generous with one’s resources actually is the most effective” strategy, said one of the study’s authors.
“Fundamentally, the paper is about the intersection of kindness and success — how being generous with one’s resources actually is the most effective” strategy, said one of the study’s authors.Pete Kiehart for The New York Times

They developed an epidemiological model to simulate how a virus might spread through a midsize university, like Colorado Mesa University, one of the schools Dr. Sabeti’s team has been advising. (Several C.M.U. officials and researchers are co-authors of the paper.)

Using real-world data from C.M.U., the researchers created a baseline scenario in which 1 percent of people at the school, and 6 percent of those in the surrounding county, were infected by the coronavirus, and the university was testing 12 percent of its members every day. The team assumed that they had a complete list of each university member’s close off-campus contacts, and that if someone tested positive for the virus, they and their contacts would quarantine until they were no longer infectious.

Under these conditions, the researchers found, if the university used all of its tests on its own members, it would have roughly 200 Covid-19 cases after 40 days. But if instead it parceled out some of those tests, using them on community members who were close contacts of students and staff, the number of cases dropped by one-quarter.

“The optimal proportion of tests to use outside the institution on those targeted, first-degree contacts came out to be about 45 percent,” said Ivan Specht, an undergraduate researcher in Dr. Sabeti’s lab and a co-author of the paper. In short, institutions could reduce their caseloads by one-fourth if they used almost half their tests on people just outside their direct membership. That percentage “is remarkably high considering that most institutions use zero percent of their tests outside of themselves,” Mr. Specht noted.

The researchers then tweaked the model’s parameters in various ways: What if the virus were more prevalent? What if students and staff did not report all their contacts? What if they were better about mask-wearing and social distancing? What if the university deployed more tests, or fewer?

Unsurprisingly, the more testing the university did, and the more information it had about its members’ close contacts, the fewer Covid-19 cases there were. But in virtually every scenario, sharing at least some tests with the broader community led to fewer cases than hoarding them.

“The surprising thing is just how robust that finding is in the face of some pretty plausible variations,” said A. David Paltiel, a professor of health policy and management at Yale School of Public Health, who was not involved in the study.

Still, he noted, there were plenty of scenarios that the model didn’t test, and the paper still needs to undergo a thorough peer review.

Its predictions should also be tested in the real world, Dr. O’Connor said: “It needs to be explored and tested head-to-head with other allocation methods.”

But if the findings hold up, it would suggest that schools and other institutions that are trying to reopen safely should think beyond their own walls when they develop testing programs. “Even if your goal is only to protect the students in your care, you will still be doing the maximum to protect those students by taking care of the people in the surrounding community,” Dr. Paltiel said. “That’s a pretty strong argument.”

Some universities are beginning to adopt this outlook. C.M.U. now offers free tests to all of its students’ self-reported contacts, whether or not they are affiliated with the university, and runs a testing site that is open to local residents, said Amy Bronson, a co-chair of the university’s Covid-19 task force and an author of the paper.

And in November, the University of California, Davis, began offering free coronavirus tests to anyone who lives or works in the city. The Healthy Davis Together program, a partnership with the city, has since administered more than 450,000 tests and identified more than 1,000 people with the virus, said Brad Pollock, an epidemiologist at U.C. Davis who directs the project.

“A virus does not respect geographic boundaries,” Dr. Pollock said. “It is ludicrous to think that you can get control of an acute infectious respiratory disease like Covid-19, in a city like Davis that hosts a very large university, without coordinated public health measures that connect both the university and the community.”

There are barriers to the more altruistic approach, including internal political pressure to use testing resources in house and concerns about legal liability. But the researchers hope that their model convinces at least some institutions to rethink their strategy, not only during this epidemic but also in future ones.

“An outbreak is an opportunity to buy a lot of community good will, or to burn a lot of community good will,” Dr. Sabeti said. “We could have spent an entire year building up that relationship between organizations and institutions and their communities. And we would have done all that hard work together, as opposed to everybody turning inward.”

Why It Pays to Think Outside the Box on Coronavirus Tests

Universities and other institutions looking to protect themselves from Covid-19 may benefit from sharing their testing resources with the wider community, a new study suggests.

Last year, when the National Football League decided to stage its season in the midst of the coronavirus pandemic, it went all-in on testing. The league tested all players and personnel before they reported for summer training camp, and continued near-daily testing in the months that followed. Between Aug. 1 and the Super Bowl in early February, the N.F.L. administered almost one million tests to players and staff.

Many other organizations have sought safety in mass testing. The University of Illinois is testing its students, faculty and staff twice a week and has conducted more than 1.6 million tests since July. Major corporations, from Amazon to Tyson Foods, have rolled out extensive testing programs for their own employees.

Now, a new analysis suggests that schools, businesses and other organizations that want to keep themselves safe should think beyond strictly themselves. By dedicating a substantial proportion of their tests to people in the surrounding community, institutions could reduce the number of Covid-19 cases among their members by as much as 25 percent, researchers report in a new paper, which has not yet been published in a scientific journal.

“It’s natural in an outbreak for people to become self-serving, self-focused,” said Dr. Pardis Sabeti, a computational biologist at Harvard University and the Broad Institute who lead the analysis. But, she added, “If you’ve been in enough outbreaks you just understand that testing in a box doesn’t makes sense. These things are communicable, and they’re coming in from the community.”

The study has “really profound implications, especially if others can replicate it, said David O’Connor, a virologist at the University of Wisconsin, Madison, who was not involved in the analysis but reviewed a draft of the paper. As the pandemic enters its second year, he said, “We want to start using more sophisticated modeling and probably economic theory to inform what an optimal testing program would look like.”

Dr. Sabeti is an epidemic veteran, part of teams that responded to an Ebola outbreak in West Africa in 2014 and a mumps outbreak in the Boston area a few years later. When the coronavirus closed down the country last spring, many colleges and universities sought her advice on how to safely reopen.

At a time when testing resources were in short supply, many of these institutions were proposing intensive, expensive testing regimens focused entirely on their own members. Again and again, Dr. Sabeti suggested that universities think more broadly, and allocate some of their tests to people who might be friends, family members or neighbors of their students and employees.

“The metaphor I often used on the calls was to say, ‘You’re in a drought in a place with a lot of forest fires, and you have a shortage of fire alarms,’” she recalled. “‘And if you run out and buy every fire alarm and install it in your own house, you’ll be able to pick up a fire the moment it hits your house, but at that point it’s burning to the ground.’”

Still, convincing university officials to divert precious testing resources away from their own institutions was a hard sell, Dr. Sabeti said, especially without data on the effectiveness of the approach. So she and her colleagues decided to gather some.

“Fundamentally, the paper is about the intersection of kindness and success — how being generous with one’s resources actually is the most effective” strategy, said Kian Sani, one of the study’s authors.
“Fundamentally, the paper is about the intersection of kindness and success — how being generous with one’s resources actually is the most effective” strategy, said Kian Sani, one of the study’s authors.Pete Kiehart for The New York Times

They developed an epidemiological model to simulate how a virus might spread through a midsize university, like Colorado Mesa University, one of the schools Dr. Sabeti’s team has been advising. (Several C.M.U. officials and researchers are co-authors of the paper.)

Using real-world data from C.M.U., the researchers created a baseline scenario in which 1 percent of people at the school, and 6 percent of those in the surrounding county, were infected by the coronavirus, and the university was testing 12 percent of its members every day. The team assumed that they had a complete list of each university member’s close off-campus contacts, and that if someone tested positive for the virus, they and their contacts would quarantine until they were no longer infectious.

Under these conditions, the researchers found, if the university used all of its tests on its own members, it would have roughly 200 Covid-19 cases after 40 days. But if instead it parceled out some of those tests, using them on community members who were close contacts of students and staff, the number of cases dropped by one-quarter.

“The optimal proportion of tests to use outside the institution on those targeted, first-degree contacts came out to be about 45 percent,” said Ivan Specht, an undergraduate researcher in Dr. Sabeti’s lab and a co-author of the paper. In short, institutions could reduce their caseloads by one-fourth if they used almost half their tests on people just outside their direct membership. That percentage “is remarkably high considering that most institutions use zero percent of their tests outside of themselves,” Mr. Specht noted.

The researchers then tweaked the model’s parameters in various ways: What if the virus were more prevalent? What if students and staff did not report all their contacts? What if they were better about mask-wearing and social distancing? What if the university deployed more tests, or fewer?

Unsurprisingly, the more testing the university did, and the more information it had about its members’ close contacts, the fewer Covid-19 cases there were. But in virtually every scenario, sharing at least some tests with the broader community led to fewer cases than hoarding them.

“The surprising thing is just how robust that finding is in the face of some pretty plausible variations,” said A. David Paltiel, a professor of health policy and management at Yale School of Public Health, who was not involved in the study.

Still, he noted, there were plenty of scenarios that the model didn’t test, and the paper still needs to undergo a thorough peer review.

Its predictions should also be tested in the real world, Dr. O’Connor said: “It needs to be explored and tested head-to-head with other allocation methods.”

But if the findings hold up, it would suggest that schools and other institutions that are trying to reopen safely should think beyond their own walls when they develop testing programs. “Even if your goal is only to protect the students in your care, you will still be doing the maximum to protect those students by taking care of the people in the surrounding community,” Dr. Paltiel said. “That’s a pretty strong argument.”

Some universities are beginning to adopt this outlook. C.M.U. now offers free tests to all of its students’ self-reported contacts, whether or not they are affiliated with the university, and runs a testing site that is open to local residents, said Amy Bronson, a co-chair of the university’s Covid-19 task force and an author of the paper.

And in November, the University of California, Davis, began offering free coronavirus tests to anyone who lives or works in the city. The Healthy Davis Together program, a partnership with the city, has since administered more than 450,000 tests and identified more than 1,000 people with the virus, said Brad Pollock, an epidemiologist at U.C. Davis who directs the project.

“A virus does not respect geographic boundaries,” Dr. Pollock said. “It is ludicrous to think that you can get control of an acute infectious respiratory disease like Covid-19, in a city like Davis that hosts a very large university, without coordinated public health measures that connect both the university and the community.”

There are barriers to the more altruistic approach, including internal political pressure to use testing resources in house and concerns about legal liability. But the researchers hope that their model convinces at least some institutions to rethink their strategy, not only during this epidemic but also in future ones.

“An outbreak is an opportunity to buy a lot of community good will, or to burn a lot of community good will,” Dr. Sabeti said. “We could have spent an entire year building up that relationship between organizations and institutions and their communities. And we would have done all that hard work together, as opposed to everybody turning inward.”

Is It Safe to Go Back to Group Exercise Class at the Gym?

Indoor fitness classes, which often result in heavy breathing in poorly ventilated rooms, can be risky. Here’s a guide to help you decide if your gym is doing enough to prevent the spread of Covid-19.

Last summer, a 37-year-old fitness instructor in Hawaii taught a spin class to 10 people. He was perched on a bike in the front of the room, facing his students as he shouted instructions and encouragement. The doors and windows were closed, but three large floor fans created a breeze to keep everyone cool. As a precaution against Covid-19, all the bikes were spaced at least six feet apart. (At the time, the gym didn’t require people to wear masks.)

But just four hours after class, the instructor began feeling fatigued. By the morning he had chills, body aches, a cough and other respiratory symptoms. Soon, he tested positive for Covid-19, and eventually, everyone who attended his class that day tested positive, too.

The outbreak didn’t stop there, though. A 46-year-old fitness instructor who attended the spin class went on to infect another 11 people during personal training sessions and kickboxing classes over the next few days, before falling ill himself and landing in intensive care.

The case of the Hawaii spin instructor was alarming because of the efficiency with which the virus left his respiratory tract and swirled around the enclosed classroom, reaching every person in the room. Among epidemiologists, that’s known as a 100 percent attack rate, and it’s a lesson in why group fitness classes, which often encourage high-energy huffing and puffing in poorly ventilated classrooms present such a daunting challenge to infection control.

At the same time, most public health experts agree that the drop in physical activity and weight gain that many people experienced during a year of pandemic living presents another set of risks to human health, and that communities need to find a balance between infection control and allowing people to return to their favorite fitness activities.

In the United States, gyms and fitness programs have reopened in some capacity in every state, allowing an estimated 73 million eager members to return to exercise. For the first time in more than a year, indoor group fitness classes were allowed to resume in New York City as of Monday, albeit at 33 percent capacity, and face coverings will be required.

The good news is that it’s possible to lower the risk of group fitness classes by improving ventilation, limiting class size, wearing a mask and increasing physical distance between participants.

Linsey Marr, an engineering professor at Virginia Tech and one of the world’s leading experts on viral transmission, is an avid exerciser herself and longed to return to her CrossFit sessions as the pandemic wore on. She worked with the owner of the gym, examining building plans and calculating potential class size and ventilation patterns in the facility.

Dr. Marr said the challenge with group fitness classes is that the participants often are breathing heavily. During a workout, people exhale and inhale at far higher volumes than when at rest.

“If someone is there who happens to be infected, they are releasing more virus into the air,” Dr. Marr said. “And the people around them are breathing heavily too, so they’re taking more in. You get this multiplicative factor. You’re breathing four times as hard, and the person who is sick is breathing four times as hard, so you’re breathing in 16 times more than you would under nonexercise conditions.”

Because of the potential for heavy breathing, Dr. Marr suggested increasing the physical distance between participants at the workout space to 10 feet rather than the standard recommendation of six feet. To achieve that level of spacing, it required limiting the class size at Dr. Marr’s workouts to just 10 people.

The facility took additional measures to minimize the chances of infection.

The solution was to open multiple garage-style doors, even in the middle of the Virginia winter. To make sure the ventilation was adequate, the gym acquired a carbon dioxide monitor to measure the buildup of carbon dioxide in a room. Because humans exhale carbon dioxide, its level can be an indicator of how well a room is ventilated.

Under everyday conditions, such as while shopping at a supermarket, an indoor carbon dioxide reading of 800 parts per million suggests that ventilation levels are adequate to reduce the risk of breathing in other people’s exhaled germs. But given the heavy breathing that occurs during a workout, Dr. Marr advised trying to keep indoor carbon dioxide levels even lower, to around 500 parts per million, and to increase ventilation if the number begins to creep toward 600.

Wearing a mask during exercise is recommended by the Centers for Disease Control and Prevention, but Dr. Marr noted that with heavy breathing, mask material can quickly get moist and lose its effectiveness. “The level of protection provided by masks is so variable that we cannot rely on them alone,” she said.

So far, the strategy seems to be working. Dr. Marr said her gym hasn’t experienced any coronavirus outbreaks, even though her state doesn’t require gym goers to wear masks while exercising. “We figured out if we kept all the doors open it should be pretty low risk,” she said. “But it was cold!”

There was one instructor who contracted the virus from somewhere outside the facility, but the well-ventilated room and rules about physical distancing appear to have protected 50 people who were exposed to him during several different classes.

While Dr. Marr’s gym is just a single case study, it shows that group fitness classes can continue safely during the pandemic, provided the facility focuses on ventilation and enforces distancing precautions and capacity limits. (Dr. Marr notes that CrossFit Inc. invited her to join its medical advisory board in December, and she helped craft a set of safety recommendations.)

We asked Dr. Marr and other experts to answer questions about how participants can decide whether their fitness class is safe to attend. Here’s what they had to say.

Does the type of exercise in the classroom make a difference?

Yes. While Covid can spread in any type of indoor class, risk is likely to go up as exercise intensity increases because breathing rates increase.

The volume of air someone breathes in and out every minute is called the “minute ventilation rate,” said Dr. Michael Koehle, the director of the Environmental Physiology Laboratory at the University of British Columbia and an expert on respiration during exercise. It naturally rises more during strenuous workouts, such as spin or dance classes, than in lighter workouts, such as yoga or Pilates.

“At low intensities — yoga, Pilates and some strength work — you can breathe more through your nose, which is a natural filter,” said Dr. Koehle. “Another very important factor is that it is more comfortable to wear a mask during strength training and lower-intensity exercise than high-intensity exercise. People should still be wearing masks indoors.”

This past August, an outbreak occurred among high-intensity exercisers at a fitness facility in Chicago. Everyone brought their own weights and mats, but not everyone wore masks. In that case, 55 out of 81 people (68 percent) who attended classes over an eight-day period at one facility came down with Covid-19. Early in the pandemic, 112 people in South Korea who took part in Zumba classes, or spent time with someone who did, were infected.

How will I know if the room has adequate ventilation?

While gyms and fitness classes are advised to meet certain ventilation standards, it’s tough for the average person to know whether a building ventilation system is adequate for infection control. “High ceilings are good,” said Dr. Marr. “If you can smell someone else, that’s a bad sign.”

Ideally, a group class should be held in a room with open windows and doors on opposite sides of the room to allow for cross ventilation. A classroom with only one entrance and no windows — a common situation in many gyms — probably does not have adequate ventilation to keep you safe. Adding several portable air cleaners to a space that lacks more doors or windows could help. “It would be much better if you can get cross ventilation — opening doors or windows on opposite sides,” said Dr. Marr. “That’s what we specified in my gym, at least two open on opposite sides.”

Do fans help?

Overhead exhaust fans or window fans that pull air out of the room are fine. But avoid any class that uses fans to recirculate air and cool down the room. Fans that recirculate air in the room just increase the risk of viral spread.

How far apart should I stand?

While six feet of distancing is recommended by public health officials for most situations, Dr. Marr advises extending it to at least 10 feet — in front of you, to either side, and behind you — during exercise.

The rules vary by state. In Massachusetts, for instance, indoor classes must have enough room for people to stand 14 feet apart. If barriers between participants are installed, then six feet is considered adequate. South Carolina requires a 10-foot by 10-foot area (100 square feet) per person; New Jersey requires twice that. Montana has required fitness classes to take place outdoors, while South Dakota has no guidance. (You can find more details about different state requirements here.)

How many people should be in the class?

States have different rules for class size, with some limiting attendance to 25 percent to 40 percent of capacity, and others allowing no more than nine or 10 people per class. Dr. Marr notes that class size is best determined by how far apart people can stand. When people keep 10 feet of distance from one another on all sides, that often limits the class size to 10 people or fewer. If you can’t achieve that much space between you and other participants, including the instructor, it’s time to find a new class.

Do I need to wear a mask?

It’s a good idea to wear a mask, and many states require them, but you can’t rely on your mask to protect you entirely. Mask quality varies, and during exercise, masks get moist, reducing their filtering efficiency. And while many gyms require masks to enter, mask wearing often is not enforced or even required during exercise classes.

In the Chicago and Hawaii outbreaks, most people were not wearing masks. At the Hawaii gym, two participants wore masks during kickboxing sessions, but their infected instructor did not, and both became ill. The C.D.C. advises that “to reduce SARS-CoV-2 transmission in exercise facilities, employees and patrons should wear a mask, even during high-intensity activities.”

Is there a way to monitor the air in my fitness class?

Not every facility will have a carbon dioxide monitor, but it’s worth asking your facility if they have one in the group fitness room and whether you can check it. If the carbon dioxide levels are below 600 parts per million (the closer to 500 the better), it’s a sign that the room ventilation is adequate for exercise. If the numbers start to increase, ask to open a window or door — or leave the class. When Dr. Marr was attending an indoor swimming pool, she noticed ventilation levels in the room were poor, so she left.

Is there a way to know if my gym has made a commitment to Covid safety precautions?

The International Health, Racquet and Sportsclub Association, an industry group, has an initiative called the IHRSA Active & Safe Commitment to follow industry best practices to provide a safe environment. Facilities that sign the pledge promise to adhere to physical distancing and mitigation measures, safety protocols and contact tracing.

The IHRSA urges the gym to have a list of protocols on its website and at the facility. At the bare minimum, protocols should include ventilation and fresh air exchange, capacity limits, distancing protocols and a clear mask policy. “I would specifically ask about ventilation practices, if mask wearing at all times is mandatory, and if classes and equipment were to be spaced out to allow for appropriate social distancing,” said Cedric Bryant, president and chief science officer for the American Council on Exercise.

What if I’ve been vaccinated?

Your risk for contracting coronavirus or developing serious illness drops dramatically if you’ve been vaccinated, but people who are vaccinated are still advised to take the same precautions as everyone else in public settings. And in most states, the people most likely to go to gyms or instruct a fitness class are younger and healthier, and therefore less likely to be among the first groups to be vaccinated. According to the IHRSA, 73 percent of gym and fitness class participants are 55 and younger.

Does cleaning and disinfection make a difference?

While everyone should wash their hands and wipe down gym equipment, patrons should not judge a gym solely on how often it promises to clean and sanitize an area. “We should still do what we did before, which is wipe down your machine when you’re done,” said Dr. Marr. “Maintaining a normal level of cleaning is appropriate. But any extra time and effort a gym has, put it toward cleaning the air.”

Dr. Marr notes that proper ventilation, physical distancing and class size limits will have the biggest impact on your safety. She recently posted on Twitter that ventilation is so important, she even had a nightmare about it.

“I had my first Covid-19 related nightmare (that I remember),” Dr. Marr’s tweet read. “I finished a hard, group workout in a gym. I looked around and panicked because I saw that all the doors were closed.”

Do you have a health question? Ask Well

How to Celebrate the Spring Holidays Safely With Your Family

Easter, Passover and Ramadan will be a little less lonely this year as more people get vaccinated. But experts say we can’t let down our guard just yet.

The weather is warming, the days are looking brighter and the number of people getting vaccinated is on the rise. So can we finally celebrate the spring holidays together like we used to, back when we could see the bottom halves of everyone’s faces?

Well, not exactly.

Although coronavirus cases and deaths are declining nationwide and the Centers for Disease Control and Prevention recently issued new, looser safety guidelines for vaccinated people, the agency recommended against unmasked indoor gatherings with unvaccinated people except in certain circumstances.

We asked public health experts to help us understand the latest guidance and offer advice on how to safely observe upcoming holidays like Easter, Passover and Ramadan.

Do we need to wear masks and stay six feet apart?

According to the C.D.C., if the people in your home have been fully vaccinated, meaning at least two weeks have passed since each person’s final shot, you can spend time together unmasked with the unvaccinated members of one other household — either indoors or outdoors — without physical distancing. But this holds true only if all of the unvaccinated people are not at increased risk of severe illness if they were to contract Covid-19, the agency said.

The risk of transmission between a vaccinated household and an unvaccinated household “is incredibly low,” said Dr. Joshua Barocas, an infectious diseases physician at Boston Medical Center.

And when both households are vaccinated, the risk is even lower, he added.

Erica Fleischer, 42, a public policy expert and mother of two who lives in Chicago, said her family would typically celebrate Passover Seder, held on the first two nights of the eight-day holiday, at her in-laws’ home, surrounded by as many as 20 people.

Last year they met virtually, but this year, given the new C.D.C. guidance, her unvaccinated family will have a small dinner with her in-laws, who have each received the vaccine.

Ms. Fleischer said she feels “pretty confident” the risks of infecting one another are low. “I think I actually needed more convincing than my in-laws did.”

Dr. Shaun Din, 35, a radiation oncologist in Manhattan, is planning to spend part of the holy month of Ramadan with nearby family members. Five of the eight adults, including Dr. Din and his parents, have been vaccinated, so the family feels comfortable meeting unmasked on weekends for the evening iftars that break each daylong fast.

“Last year was very lonely, not being able to celebrate together,” Dr. Din said. “Ramadan is difficult, but the communal aspect of all of us going through it and then breaking the fast together is something that’s very fun.”

Can we invite more than one household?

If you are fully vaccinated and you would like to invite other fully vaccinated friends over for dinner, the C.D.C. says that “it is likely a low risk,” and there is no need to wear masks or stay physically distanced.

Even so, keep the get-together small. The C.D.C. advises against medium- or large-size gatherings (though it hasn’t defined what constitutes medium or large).

“Variants are circulating, and the vaccines might not be quite as effective against them,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who studies viruses in the air.

If you plan to mix unvaccinated people from multiple households, experts suggest holding the gathering outside, staying six feet apart and wearing masks.

And if you decide to spend time indoors with unvaccinated people from other households, wear a mask and open the windows to improve the ventilation, said Shelly Miller, a mechanical engineering professor at the University of Colorado, Boulder, who studies airborne disease transmission in enclosed spaces. She also suggested using a HEPA filter air cleaner certified by the Association of Home Appliance Manufacturers.

What about unvaccinated kids?

The coronavirus vaccine is not currently available to most children because clinical trial results are still forthcoming.

Say there are two healthy families of four. If the kids aren’t vaccinated in either household but all of the adults are, you might consider inviting people inside as long as the windows are open and everyone is wearing masks, said Dr. Asaf Bitton, a primary care physician who runs a public health research laboratory at Brigham and Women’s Hospital in Boston. If the kids in neither household are vaccinated and only one set of adults has been vaccinated, he and other experts said an outdoor gathering with masks and distancing would be safest.

You may also be wondering if your unvaccinated children can finally get a hug and kiss from their healthy, vaccinated grandma. On this question, the experts’ opinions diverged. But in general, if everyone is healthy and you’re comfortable accepting some degree of risk, a hug or kiss is probably fine.

“The likelihood that my kid transmits a virus that ends up causing severe disease in my vaccinated parents is very, very low,” Dr. Barocas said.

Similarly, he added, it’s unlikely that a vaccinated adult would transmit the virus to a child. That said, the experts advised doing what feels right to you and your family.

“I think everyone going into that visit needs to understand that we’re balancing risks and benefits,” said Dr. Adam Ratner, director of the division of pediatric infectious diseases at Hassenfeld Children’s Hospital at N.Y.U. Langone. But, he added, if the grandparents are vaccinated, “I am pro hugging and kissing.”

Jennifer Rogers, 46, an attorney in Philadelphia, said her husband and two children, 8 and 11, will celebrate Easter by visiting her parents’ home for several hours. They’re planning on having an outdoor Easter egg hunt and whacking away at a coronavirus-shaped piñata. But the kids, who will be joined by Ms. Rogers’s sister and her sister’s son, will all be wearing masks. Ms. Rogers and her husband are both vaccinated, but they are planning to wear masks too, because their family will have recently returned from a Florida vacation.

“It still feels like a loss, like it’s not the same as it’s been,” said Ms. Rogers, whose family typically stays overnight at her parents’ home during the holiday.

Can our fully vaccinated relatives fly out to see us?

The C.D.C. is still saying no.

“We know that after mass travel, after vacations, after holidays, we tend to see a surge in cases,” the C.D.C. director, Dr. Rochelle Walensky, said last week on MSNBC. “And so, we really want to make sure — again with just 10 percent of people vaccinated — that we are limiting travel.”

We are also still learning whether vaccinated people without symptoms can unknowingly carry infections to the households that they are visiting, Dr. Bitton said.

“Travel in little metal tubes and crowded airports and taxi cabs brings risks of transmission,” he added.

Danielle Nuzzo, 36, a communications manager whose family celebrates both Easter and Passover, lives in California with her husband and 2-year-old daughter, across the country from both sets of grandparents. As soon as the grandparents got vaccinated, they asked if they could visit during the holidays, she said. But Ms. Nuzzo and her husband are not vaccinated yet, and they didn’t feel comfortable hosting anyone who had just hopped off a plane. In the end, they decided they will celebrate just like they did last year, over Zoom.

“It’s really hard. It’s emotional,” Ms. Nuzzo said. “We want her to know who her grandparents are and see them. But we also want to do what’s right and just be safe.”

If your family does decide to travel, the C.D.C. recommends first getting fully vaccinated for the coronavirus, if you are eligible, and also getting a Covid-19 test one to three days before the trip. All travelers, regardless of whether they are vaccinated or not, must wear a mask; try to stay at least six feet from others; get tested again three to five days after your trip and quarantine for seven days, even if your test is negative. (If you don’t get tested, the C.D.C. says you should quarantine for 10 days.)

Check your state and local requirements because different areas have different rules. New York State, for example, says domestic travelers do not need to quarantine during the first three months after being fully vaccinated, provided that they are asymptomatic.

What if my relatives and I disagree about what’s safe?

After a year of public health warnings, some family members might feel uneasy about loosening the rules while others might be anxious to get back to normal.

Last year, ahead of the Thanksgiving holiday, Claudia W. Allen, a clinical psychologist and the director of the Family Stress Clinic at the University of Virginia School of Medicine, told The New York Times that if there are differences of opinion, it’s important not to pass judgment, start lecturing or assume that your relatives have bad motives.

“The people who are willing to take more risks are usually doing it because they’re valuing connection. And the people who are less willing to take risks are usually less willing because they are prioritizing safety. Connection and safety are both good,” Dr. Allen said at the time.

The same advice applies for spring holidays. “A new tricky aspect is that some people are vaccinated and others aren’t,” she added this week.

If you’re at odds with a family member, don’t forget to recognize the other person’s good intentions, even if you ultimately have to agree to disagree, Dr. Allen said. Take a moment to also acknowledge their feelings and the uncertainty of the situation and say, “I totally understand your caution; we each have to try to weigh the risks as best we can.”

Three Feet or Six? Distancing Guideline for Schools Stirs Debate

Some public health officials say it’s time for the C.D.C. to loosen its social distancing guidelines for classrooms, but the idea has detractors.

The Centers for Disease Control and Prevention is clear and consistent in its social distancing recommendation: To reduce the risk of contracting the coronavirus, people should remain at least six feet away from others who are not in their households. The guideline holds whether you are eating in a restaurant, lifting weights at a gym or learning long division in a fourth-grade classroom.

The guideline has been especially consequential for schools, many of which have not fully reopened because they do not have enough space to keep students six feet apart.

Now, spurred by a better understanding of how the virus spreads and a growing concern about the harms of keeping children out of school, some public health experts are calling on the agency to reduce the recommended distance in schools from six feet to three.

“It never struck me that six feet was particularly sensical in the context of mitigation,” said Dr. Ashish Jha, dean of the Brown University School of Public Health. “I wish the C.D.C. would just come out and say this is not a major issue.”

On Sunday, Dr. Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases, said on CNN that the C.D.C. was reviewing the matter.

The idea remains contentious, in part because few studies have directly compared different distancing strategies. But the issue also boils down to a devilishly difficult and often personal question: How safe is safe enough?

“There’s no magic threshold for any distance,” said Dr. Benjamin Linas, a specialist in infectious diseases at Boston University. “There’s risk at six feet, there’s risk at three feet, there’s risk at nine feet. There’s risk always.” He added, “The question is just how much of a risk? And what do you give up in exchange?”

The origins of six feet

The American Academy of Pediatrics recommends three to six feet of social distancing in schools, while the World Health Organization recommends just one meter, or 3.3 feet.
The American Academy of Pediatrics recommends three to six feet of social distancing in schools, while the World Health Organization recommends just one meter, or 3.3 feet.Pete Kiehart for The New York Times

The origin of the six-foot distancing recommendation is something of a mystery. “It’s almost like it was pulled out of thin air,” said Linsey Marr, an expert on viral transmission at Virginia Tech University.

When the virus first emerged, many experts believed that it was transmitted primarily through large respiratory droplets, which are relatively heavy. Old scientific studies, some dating back more than a century, suggested that these droplets tend not to travel more than three to six feet. This observation, as well as an abundance of caution, may have spurred the C.D.C. to make its six foot suggestion, Dr. Marr said.

But that recommendation was not universal. The American Academy of Pediatrics recommends three to six feet of social distancing in schools, but the World Health Organization recommends just one meter, or 3.3 feet.

And over the last year, scientists have learned that respiratory droplets are not the primary mode of coronavirus transmission. Instead, the virus spreads mostly through tiny airborne droplets known as aerosols, which can travel longer distances and flow through rooms in unpredictable ways.

Data also suggests that schools appear to be relatively low-risk environments; children under 10 seem to transmit the virus less readily than adults.

In recent months, there have been hints that six feet of distancing may not be necessary in school settings. Case rates have generally been low even in schools with looser distancing policies. “We know lots of schools have opened up to less than six feet and have not seen big outbreaks,” said Dr. Jha.

In a 2020 analysis of observational studies in a variety of settings, researchers found that physical distancing of at least one meter substantially reduced transmission rates of several different coronaviruses, including the one that causes Covid-19. But they found some evidence to suggest that a two meter guideline “might be more effective.”

“One of the really important data points that has been missing is a direct head-to-head comparison of places that had implemented three feet of distance versus six feet of distance,” said Dr. Elissa Perkins, the director of emergency medicine infectious disease management at Boston University School of Medicine.

A natural experiment

A hand sanitizer station in a Catholic school in Boston in January.Allison Dinner/Reuters

Dr. Perkins and her colleagues recently conducted such a comparison by taking advantage of a natural experiment in Massachusetts. Last summer, the state’s education department issued guidelines recommending three to six feet of distancing in schools that were planning to reopen in the fall. As a result, school policies varied: Some districts imposed strict, six-foot distancing, whereas others required just three. (The state required all staff members, as well as students in second grade and above, to wear masks.)

The researchers found that the social distancing strategy had no statistically significant effect on Covid-19 case rates, the team reported in the journal Clinical Infectious Diseases last week. The study also found that Covid-19 rates were lower in schools than in the surrounding communities.

The authors say the findings provide reassurance that schools can loosen their distancing requirements and still be safe, provided they take other precautions, like enforcing universal mask wearing.

“Masking still appears to be effective,” said lead investigator Dr. Westyn Branch-Elliman, an infectious diseases specialist at the VA Boston Healthcare System. “And so, provided we have universal masking mandates, I think it’s very reasonable to move to a three-foot recommendation.”

Not everyone finds the study so convincing. A. Marm Kilpatrick, an infectious disease researcher at the University of California, Santa Cruz, said that the school-district data was too noisy to draw firm conclusions from. “It doesn’t really allow you to get, I think, an answer that you can feel really confident in,” he said.

The study’s authors acknowledged that they could not rule out the possibility that increased distancing provided a small benefit.

With aerosol transmission, safety generally increases with distance; the farther the aerosols travel, the more they diluted become. “It’s like being close to a smoker,” Dr. Marr said. “The closer you are, the more you’re going to breathe in.”

And distance aside, the more people there are in a room, the higher the odds that one of them will be infected with the coronavirus. A six-foot rule helps reduce that risk, said Donald Milton, an aerosol expert at the University of Maryland: “If people are six feet apart, you can’t pack them in. And so, it’s safer just because it’s less dense.”

Masks and good ventilation do a lot to reduce the risk. With these measures in place, the difference between three and six feet was likely to be relatively small, scientists said. And if Covid-19 is not very prevalent in the surrounding community, the absolute risk of contracting the virus in schools is likely to remain low, as long as these protections are in place.

“We can always do things to reduce our risks further,” Dr. Marr said. “But at some point, you reach diminishing returns, and you have to think about the costs of trying to achieve those additional risk reductions.”

Debate and diminishing risks

“Provided we have universal masking mandates, I think it’s very reasonable to move to a three-foot recommendation,” said one infectious disease specialist.Rosem Morton for The New York Times

Some experts say that a small increase in risk is outweighed by the benefits of fully reopening schools. “Trying to follow the six-foot guideline should not prevent us from getting kids back to school full time with masks, with at least three-foot distancing,” Dr. Marr said.

Others said it was too soon to loosen the C.D.C. guidelines. “Ultimately, I think there could be a place for this changing guidance,” Saskia Popescu, an infectious disease epidemiologist at George Mason University, said in an email. “But it’s not now, when we are struggling to vaccinate people, we’re still seeing over 60,000 cases a day and we’re trying to not reverse the progress we’ve made.”

Even proponents of changing the guideline say that any shift to looser distancing will have to be done carefully, and in combination with other precautionary measures. “If you’re in an area where there’s not a strong tendency to rely on masks, I don’t think it would be wise to extrapolate our data to that environment,” Dr. Perkins said.

Moreover, officials risk muddying the public health messaging if they establish different standards for schools than for other shared spaces. “I’ve evolved on this,” Dr. Linas said. “Last summer I felt like, ‘How are we going to explain to people that it’s six feet everywhere except for schools? That seems not consistent and problematic.’”

But schools are unique, he said. They are relatively controlled environments that can enforce certain safety measures, and they have unique benefits for society. “The benefits of school are different than the benefits of movie theaters or restaurants,” he said. “So I’d be willing to assume a little bit more risk just to keep them open.”

At-Home Covid Testing Is Here

At-Home Covid Testing Is Here

But does it work?

Credit…Rose Wong

  • Feb. 26, 2021, 12:44 p.m. ET

In case you missed it: You can now get tested for the coronavirus in the comfort of your own home.

This is great news, especially for people who don’t have access to a testing site. Currently, these portable tests come in two flavors. The first is test-by-mail kits, which allow patients to swab their noses at home and mail them to a laboratory for a result in a day or two. The other types are called at-home tests, which give an answer on the spot.

Currently, the United States Food and Drug Administration has authorized dozens of test-by-mail kits, and three at-home tests.

These tests are not nearly as accurate as those taken in a clinic, but experts say coronavirus tests that can be done at home play an important role as the country continues to reopen. “They get actionable information in people’s hands quickly,” said Jennifer Bacci, an assistant professor at the University of Washington School of Pharmacy.

Of course, no coronavirus diagnostic test is 100 percent accurate. Even the gold-standard nasopharyngeal swab, given at many clinics, can return a negative result even though you might be carrying the coronavirus. And these tests only inform you about a single point in time. But even if home tests may be less accurate, they can quickly alert people if they test positive.

Certainly the market for home test kits will likely grow, said Gigi Gronvall, a public health expert at Johns Hopkins University. But with more options, consumers will need to learn what test is best for them.

Here are some key questions to consider when deciding on an at-home testing kit.

What are the trade-offs between mail-in kits and fully at-home tests?

Test-by-mail kits require users to purchase a kit, take a sample at home and ship the swab back to a lab. These kits take more processing time and use a method called polymerase chain reaction, or P.C.R., to detect coronavirus.

P.C.R. works by identifying and magnifying specific gene sequences. “It can take a very small signal and amplify it,” to detect smaller amounts of the virus, said Dr. Gronvall. These tests are highly sensitive, picking up positive cases nearly all the time (accuracy varies by lab, and false negatives can be as high as 20 percent). “A negative P.C.R. isn’t perfect, but it gives a high degree of assurance,” said Dr. Ashish Jha, dean of the Brown University School of Public Health.

Fully at-home tests, such as those made by Ellume and Abbott, require users to swab their noses and drop the swabs in a liquid. The tests provide an answer in as little as 15 minutes for the Abbott test and 20 minutes for Ellume.

These tests look for antigens — parts of microbes that cause an immune response. Unlike P.C.R., antigen tests do not amplify signals, which makes them faster but less accurate. These rapid antigen tests, Dr. Gronvall said, are good for measuring how contagious you are. “If you test positive on that, you really need to isolate,” she said, and get a clinical swab done to confirm the results.

False negatives, however, are much more common with antigen tests, meaning infected people might think they are virus free, especially if they are not having symptoms.

“The sensitivity of these tests tend to be pretty bad,” said Dr. Yvonne Maldonado, an infectious disease specialist at Stanford University School of Medicine. If users have symptoms, the BinaxNOW antigen test has a 64 percent chance of correctly spotting the virus (and about half that in those without symptoms). Accuracy for some antigen tests in asymptomatic individuals can be less than 50 percent — worse than flipping a coin, she said.

Remember, any test’s ability to detect coronavirus depends on how much virus is in the location of your body where you are taking a sample. Tests taken early, say, hours after a potential virus exposure, have a higher chance of being a false negative.

What home test should you use?

If you’re asymptomatic, you may have a smaller amount of virus in your body. In this case, experts said that your best bet for an accurate test is to use a test-by-mail kit because P.C.R. will be able to amplify lower levels of virus.

If you have symptoms, either a P.C.R.-based test or an antigen test will likely be able to confirm you have it. When choosing an antigen test, Dr. Jha said to look for whichever option at your disposal has the highest sensitivity, which refers to a test’s ability to detect the virus. Look for a sensitivity rating from 95 to 99 percent, he said.

Turnaround time is also important. Antigen tests are less accurate but offer an answer much faster without having to mail a sample. Results of either test should always be confirmed by a clinical test, said Dr. Maldonado.

Costs, too, may play a factor. Test-by-mail kits can cost $100 or more and may not be reimbursed by insurance companies. “Many patients have encountered unanticipated bills or red tape when seeking reimbursement for mail-in coronavirus testing, even though insurance companies are obligated to do so,” said Dr. Marisa Cruz, head of clinical affairs at Everlywell, a company that makes at-home health tests, including one for coronavirus.

Antigen tests, on the other hand, are a fraction of the cost, currently ranging from $25 to $50.

What should you check for on the box?

Make sure the home test or collection kit you’re looking to buy has an emergency use authorization from the F.D.A. (it will be printed on the box) and that the company works with certified lab partners. Also look for tests that offer a telemedicine consult, advised Dr. Cruz, so you can discuss your diagnosis and next steps.

How should I interpret a result from an at-home coronavirus test?

Following the test kit instructions is key to getting a reliable result. “A specimen that is not collected correctly may lead to false negative test results,” said Dr. Cruz. Imperfect swabbing technique, or swabbing only one nostril, may increase the risk of less accurate results. And samples for test-by-mail kits should be shipped the same day they are collected; the less time in transit, the better. Samples sent on weekends or holidays may be delayed, though some use FedEx and overnight shipping.

If you test positive on either a mail-in P.C.R. or at-home antigen test, you are likely to be infected and presumed contagious, said Dr. Bacci, so isolate from others and continue to monitor your symptoms. Repeat testing can help track the disease course, if, say, someone goes from being asymptomatic to displaying symptoms.

Negative results are more likely to be wrong than positive ones. “A negative result does not necessarily mean you do not have Covid, which is the same interpretation for either an at-home test, a mail-in test or one offered in a doctor’s office,” said Dr. Cruz. Continue to wear masks, socially distance and practice good hygiene, especially if you have symptoms or known contacts with others with Covid.

When would a test be inappropriate to use?

Dr. Gronvall is concerned that some people are using at-home tests after they’ve been vaccinated to make sure that the vaccine has worked. But neither the P.C.R. or antigen-based tests will be able to discern whether the vaccines have built up immunity in your body.

That’s because the vaccines encode for snippets of the virus and not the entire sequence. The P.C.R. and antigen tests search for a different portion of the virus from what’s included in the vaccines.

“These tests are not going to tell people if the vaccine is effective,” she said.

What does the future of at-home testing look like?

Beyond saliva and nasal swabs, some scientists are looking to develop devices that look like breathalyzers to detect chemicals in an individual’s breath that correspond to coronavirus infection. “We’re looking for the body’s response to infection and disease,” said Pelagia-Iren Gouma, a materials engineer at The Ohio State University.

Dr. Gouma and her colleagues are testing a small breathalyzer they have developed that can be used for up to one year and would cost perhaps a few dollars per device. Users would get an answer in 15 seconds, and the test appears to be accurate 96 percent of the time and can be reused, Dr. Gouma said. The device was submitted to the F.D.A. and has been awaiting emergency use authorization since September.

Experts hope that as the market for at-home testing expands, the options will grow and become cheaper. The cheaper the tests are, the more likely the government will subsidize them and consumers will buy them for routine testing. And the more testing, the better. As the world slowly reopens, home-based tests will help people make better decisions.


Wudan Yan is a journalist based in Seattle, Wash., writing about science and society.

Vacunas para covid: respuestas a preguntas clave

En resumen, sí, aunque hay algunas precauciones que debes tener en cuenta antes de quitarte la mascarilla. Pedí consejo a Ashish K. Jha, decano de la Escuela de Salud Pública de la Universidad de Brown. Dice que hay cuatro preguntas que debes hacerte si quieres pasar tiempo en interiores con otras personas vacunadas, sin cubrebocas.

– ¿Estás vacunado?

– ¿Están vacunados todos los demás?

– ¿Cuál es el nivel de propagación en la comunidad?

– ¿Hay entre ustedes alguien con alto riesgo?

Incluso si todos los presentes están vacunados, hay que pensar en las dos últimas preguntas. La vacuna ofrece un 95 por ciento de protección (un cálculo basado en datos de ensayos clínicos estrictamente controlados, no en el mundo real). Pero también hay que pensar en las probabilidades de entrar en contacto con el virus. Un cinco por ciento de riesgo de infección cuando el virus está en pleno apogeo sigue siendo un riesgo importante.

“Si el riesgo de infección es muy alto, entonces el 95 por ciento no es lo suficientemente bajo mientras la cantidad de casos sea tan alta como lo son en Estados Unidos”, dijo Jha. “La gente debería llevar un cubrebocas incluso después de la vacunación. Con el tiempo, a medida que las cifras de infección descienden, digamos que se tiene un riesgo del cinco por ciento a partir de una base baja, entonces se vuelve mucho más seguro”.

La última pregunta —si hay alguien de alto riesgo en la reunión— también es importante. Incluso si una persona de alto riesgo está vacunada, hay que tomar precauciones adicionales cuando los recuentos de casos de virus son elevados en la comunidad. Y hay que tener en cuenta que la vacuna puede no ser un 95 por ciento eficaz en todas las personas: una persona mayor o alguien con un sistema inmunitario menos eficiente puede obtener menos protección de la vacuna que una persona joven y sana.

“Aunque haya sido vacunado, durante una pandemia arrasadora y con un panorama terrible, si visito a mis padres ancianos voy a ser cuidadoso; mi tolerancia al riesgo es baja”, dijo Jha. “Voy a tener un umbral diferente con mi padre de 82 años que con mi amigo de 47 años. A medida que la pandemia disminuya, creo que vamos a poder relajarnos más”.

Desafortunadamente, gran parte de los mensajes de salud pública en torno a la vacuna han consistido en recordar a la gente que debe seguir usando mascarillas, en lugar de recordarles también que, tras la vacunación y con las precauciones adecuadas, podremos socializar de forma segura con otras personas vacunadas, sin tener que usar una mascarilla.

—Tara Parker-Pope

How to Buy a Real N95 Mask Online

Tech Fix

How to Buy a Real N95 Mask Online

Fakes and little-known brands still abound, even as health officials have advised us to up our mask game. Here’s what to do.

Credit…Glenn Harvey
Brian X. Chen

  • Feb. 17, 2021, 5:00 a.m. ET

A year into the coronavirus pandemic, buying a heavy-duty medical mask online remains downright maddening.

The most coveted mask to keep safe against Covid-19 has been the N95, the gold standard for pandemic protection because of its tight fit and 95 percent efficiency in filtering airborne particles. Then there’s the KN95 from China, a mask for medical workers, which also offers high filtration and is somewhat looser fitting.

But these masks have been far from easy to buy on the internet. When the pandemic hit last year, they immediately became scarce as health care workers and governments rushed to obtain them. The demand was so intense that a gray market sprang up for them.

Yet even after supplies have improved, it is often not easy to find authentic N95s and KN95s online. That’s because there are few brand-name makers, so it can be hard to know which of the dozens of manufacturers are reliable. And counterfeiters continue to flood the market, even on trusted sites like Amazon.

The result is frequently frustration, when wearing a heavy-duty mask is more important than ever. Last week, federal health officials emphasized the need for all of us to have tightfitting masks because of new fast-spreading coronavirus variants.

“People don’t know what’s legit, and they don’t know which suppliers are legit,” said Anne Miller, an executive director of Project N95, a nonprofit that helps people buy protective coronavirus equipment. “We’ve had that issue since the very beginning of the pandemic.”

I recently spent hours comparing masks online and almost bought a pack of counterfeits on Amazon. Thankfully, I avoided falling into the trap and eventually found legitimate, high-quality masks from a trustworthy online retailer.

Along the way, I learned plenty about how to spot fraudulent mask listings and how to sidestep fake reviews. So here’s how to home in on real medical-grade masks that will keep you and your loved ones safe.

Pick a mask

My journey began on the website for the Centers for Disease Control and Prevention. There I found charts of N95 and KN95 masks that the agency has tested, including the make, model number and filtration efficiency.

After some reading, I learned about the trade-offs between the two types of masks. The N95s typically have bands that strap over the back of your head, which is what makes them snug. They can be uncomfortable to wear for long periods.

The KN95s, which the Food and Drug Administration has approved for emergency use by health care workers, have ear loops for a tight fit that is slightly more comfortable than an N95. The downside is that the KN95 leaks a bit more air than an N95.

If you are often in high-risk areas like hospitals, N95s may be more suitable. But if you just need a protective mask for more casual use, like the occasional trip to the grocery store, KN95s are probably sufficient.

After doing the research, I decided a KN95 mask from Powecom, a Chinese brand, was best for my purposes. The mask scored 99 percent filtration efficiency in the C.D.C.’s tests.

From there, I visited Amazon, where I buy everything from dog food to batteries in the pandemic. That’s when things went awry.

Beware of Amazon

When I typed “Powecom KN95” into Amazon’s search box, the masks instantly popped up with a rating of 4.5 stars. I quickly clicked “Add to Cart.”

But before checking out, I scrolled down to read the reviews. There were about 130 — including a handful of one-star reviews from aggrieved buyers who said the masks were most likely fake. I emptied my shopping cart.

How had I almost bought a counterfeit? Saoud Khalifah, the founder of Fakespot, a company that offers tools to detect fake listings and reviews online, said a third-party seller had probably taken control of the product listing and sold fakes to make a quick buck.

“It’s a bit of a Wild West,” he said. “The normal consumers that shop on Amazon do not know that they just bought a fake mask. This is the biggest critical problem: You think it’s real, and suddenly you get sick.”

Mr. Khalifah presented other examples of questionable masks that were being sold on Amazon:

  • A pack of 50 masks was highlighted on Amazon this week as the No. 1 new release in women’s fashion scarves. Obviously, masks are not scarves, which was a giveaway that something was off. The listing description also replaced all of the letter A’s with accented characters. This was a technique used to bypass Amazon’s fraud detection systems, Mr. Khalifah said. Amazon removed the listing after I called about it.

  • Another pack of 20 masks looked attractive and was described as approved by the C.D.C. It even had positive reviews with an average of 4.4 stars. But the reviews revealed that most customers had received the masks for free, probably an incentive to leave positive feedback. One lukewarm review from someone who had paid for the product noted that the masks were “thin and very, very big.”

  • Mr. Khalifah’s software also detected that the reviewers of another pack of 100 masks, which had unanimous five-star ratings, had a history of writing promotional reviews for other brands.

Amazon said in a statement that it prohibits the sale of counterfeit products and invests to ensure its policy is followed. It said it had specific policies for N95 and KN95 masks, including a process for vetting inventory and taking action on those who sold fakes.

Amazon also said it had addressed the questionable Powecom mask that I nearly purchased, as well as the mask advertised as a scarf. It added that there was no evidence that the pack of 20 masks was counterfeited and did not comment on the pack of 100 masks.

Mr. Khalifah cautioned that the fakes he spotted on Amazon could just as easily be on websites for other big retailers, such as Walmart and eBay, that allow third-party sellers to ship products. To buy authentic masks, he said, I should take a less traditional approach to shopping online.

Order from an authorized source

Armed with this advice, I continued my search for the Powecom mask.

I visited the manufacturer’s website, which listed steps for verifying that a mask is real. That involved scanning a bar code on the package with a phone camera. Then I did a web search for the mask, which brought me to bonafidemasks.com, an online retailer that shows documentation stating that it is an authorized distributor of Powecom masks in the United States.

That was more reassuring. So I ordered a pack of 100 for $99. When the package arrived in the mail, I scanned the bar codes to confirm their authenticity. They were the real deal.

Another path I could have taken was to order masks directly from the manufacturer. Verified mask producers like DemeTech, in Miami, and Prestige Ameritech, in Texas, sell N95s through their websites.

But ordering directly from a manufacturer presents other challenges. Often you have to buy a large quantity to reduce the cost.

So what if you just want to buy a few to try on? Ms. Miller’s nonprofit Project N95 buys bulk orders of masks and breaks them up so people can buy smaller batches. “It’s a very painstaking process to go through,” she said.

No kidding.

Scientists to C.D.C.: Set Air Standards for Workplaces Now

Scientists to C.D.C.: Set Air Standards for Workplaces Now

The agency has not fully reckoned with airborne transmission of the coronavirus in settings like hospitals, schools and meatpacking plants, experts said.

Production of N95 masks at a facility in Fort Worth, Texas, earlier this month. “It’s time to stop pussyfooting around the fact that the virus is transmitted mostly through the air,” said one expert.
Production of N95 masks at a facility in Fort Worth, Texas, earlier this month. “It’s time to stop pussyfooting around the fact that the virus is transmitted mostly through the air,” said one expert.Credit…Cooper Neill for The New York Times
Apoorva Mandavilli

  • Feb. 17, 2021, 12:01 a.m. ET

Nearly a year after scientists showed that the coronavirus can be inhaled in tiny droplets called aerosols that linger indoors in stagnant air, more than a dozen experts are calling on the Biden administration to take immediate action to limit airborne transmission of the virus in high-risk settings like meatpacking plants and prisons.

The 13 experts — including several who advised President Biden during the transition — urged the administration to mandate a combination of masks and environmental measures, like better ventilation, to blunt the risks in various workplaces.

On Friday, the Centers for Disease Control and Prevention issued new guidelines for reopening schools, but quickly passed over improved ventilation as a precaution. It was only in July that the World Health Organization conceded that the virus can linger in the air in crowded indoor spaces, after 239 experts publicly called on the organization to do so.

In a letter to the administration, scientists detailed evidence supporting airborne transmission of the virus. It has become even more urgent for the administration to take action now, the experts said, because of the slow vaccine rollout, the threat of more contagious variants of the virus already circulating in the United States, and the high rate of Covid-19 infections and deaths, despite a recent drop in cases.

“It’s time to stop pussyfooting around the fact that the virus is transmitted mostly through the air,” said Linsey Marr, an expert on aerosols at Virginia Tech.

“If we properly acknowledge this, and get the right recommendations and guidance into place, this is our chance to end the pandemic in the next six months,” she added. “If we don’t do this, it could very well drag on.”

The letter was delivered on Monday to Jeffrey D. Zients, coordinator of the Biden administration’s Covid-19 response; Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention; and Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases.

Dr. Anthony S. Fauci, left, and Jeffrey D. Zients, President Biden’s Covid-19 response coordinator, at the White House last month.
Dr. Anthony S. Fauci, left, and Jeffrey D. Zients, President Biden’s Covid-19 response coordinator, at the White House last month.Credit…Doug Mills/The New York Times

The letter urged the C.D.C. to recommend the use of high-quality masks, such as N95 respirators, to protect workers at high risk of infection. At present, health care workers mostly rely on surgical masks, which are not as effective against aerosol transmission of the virus.

Many workers vulnerable to infection are people of color, who have borne the brunt of the epidemic in the United States, the experts noted.

Mr. Biden has directed the Occupational Safety and Health Administration, which sets workplace requirements, to issue emergency temporary standards for Covid-19, including those regarding ventilation and masks, by March 15.

But OSHA will only mandate standards that are supported by guidance from the C.D.C., said David Michaels, an epidemiologist at George Washington University and one of the signatories.

(Dr. Michaels led OSHA during the Obama administration; the agency has not had a permanent leader since his departure.)

“Until the C.D.C. makes some changes, OSHA will have difficulty changing the recommendations it puts up because there’s an understanding the government has to be consistent,” Dr. Michaels said. “And C.D.C. has always been seen as the lead agency for infectious disease.”

Public health agencies, including the W.H.O., have been slow to acknowledge the importance of aerosols in spreading the coronavirus. It was only in October that the C.D.C. recognized that the virus can sometimes be airborne, after a puzzling sequence of events in which a description of how the virus spreads appeared on the agency’s website, then vanished, then resurfaced two weeks later.

But the agency’s recommendations on workplace accommodations did not reflect this change.

Early in the pandemic, the C.D.C. said health care workers did not need N95 respirators, and could even wear bandannas to protect themselves. It also did not recommend face coverings for the rest of the population.

The agency has since revised those recommendations. It recently recommended that people wear two masks or improve the fit of their surgical masks to protect from the virus.

“But they don’t talk about why you need a better fitting mask,” said Dr. Donald Milton, an aerosol expert at the University of Maryland. “They’re acknowledging the importance of breathing it in and the route of transmission, and yet they don’t say it clearly in their various web pages.”

Election workers in Lansing, Mich., sorted absentee ballots in November while a ventilation duct helped to circulate air.Credit…John Moore/Getty Images

The agency recommends surgical masks for health care workers and says N95 respirators are needed only during medical procedures that generate aerosols, like certain kinds of surgery.

But many studies have shown that health care workers who have no direct contact with Covid-19 patients are also at high risk of infection and should be wearing high-quality respirators, said Dr. Céline Gounder, an infectious disease specialist at Bellevue Hospital Center in New York and an adviser to Mr. Biden during the transition.

“The C.D.C. has not emphasized the risk of aerosol transmission enough,” Dr. Gounder said. “Unfortunately, concerns about supply continue to muddy the discussion.”

Many hospitals still expect their staff to reuse N95 masks per the agency’s recommendation to reuse when supplies are low. But since the masks are no longer in short supply, the agency should change its recommendations, Dr. Gounder said.

“We really do need to stop this reuse and decontamination approach to N95s,” she added. “We’re a year into this, and that’s really not acceptable.”

Hospitals, at least, tend to have good ventilation so health care workers are protected in other ways, the experts said. But in meatpacking plants, prisons, buses or grocery stores, where workers are exposed to the virus for long periods of time, the C.D.C. does not recommend high-quality respirators, nor does it endorse upgrades to ventilation.

“If you go to other workplaces, this idea that aerosol transmission is important is virtually unknown,” Dr. Michaels said. In food processing plants, for example, a refrigerated environment and the lack of fresh air are ideal conditions for the virus to thrive. But the industry has not put in safety measures to minimize the risk, he added.

Employers instead hew to the C.D.C.’s recommendations for physical distancing and cleaning surfaces.

The recent emergence of more contagious variants makes it urgent for the C.D.C. to address airborne transmission of the virus, said Dr. Marr of Virginia Tech. Germany, Austria and France now mandate N95 respirators or other high-quality masks in public transportation and shops.

Dr. Marr was one of the experts who wrote to the W.H.O. last summer to push for an acknowledgment of airborne transmission. She did not expect to be in a similar position again so many months later, she said: “It feels like Groundhog Day.”

Get Wise to Covid Rumors

Get Wise to Covid Rumors

False information and conspiracy theories have always been a part of society but the pandemic has supercharged them. Don’t be fooled.

Credit…Nadia Hafid

  • Feb. 12, 2021, 3:03 p.m. ET

Didn’t you know? Ninety-nine percent of infected people survive Covid-19. (False.) Wearing masks will make you sick. (False.) The Covid-19 vaccine contains a microchip designed to track your movements. (False.)

By this point in the pandemic, chances are you’ve heard at least one piece of false information about masks, the virus or the emerging Covid-19 vaccines. Most likely more. This “infodemic,” as the World Health Organization termed it, has spread as fast as the virus itself, complicating efforts to contain the spread of the disease and protect the public.

[Every day, Times reporters chronicle and debunk false and misleading information that is going viral online. Read the latest.]

“Conspiracy theories appear in every disease outbreak,” said Anna Muldoon, co-author of “Covid-19 Conspiracy Theories.” The widespread stress and trauma of the pandemic — combined with all the time people are spending indoors, glued to their screens — have supercharged the spread of false information. But there are steps you can take to make sure you and your loved ones aren’t falling for it.

Recognize it’s reasonable to have questions.

Effective false information usually contains a grain of truth. For instance, it’s true that the timeline from identifying SARS-CoV-2, the virus that causes Covid-19, and developing successful vaccines, was incredibly short. “I think it’s quite reasonable for people to be a little hesitant,” said Adewole Adamson, a doctor and professor at the University of Texas at Austin who studies the impact of race on medical care.

One big appeal of conspiracy theories is that they seem to offer fast, straightforward answers in a way that evidence-based science just can’t. That’s because they’re not beholden to evidence or the truth: Misinformers are free to make up whatever inflammatory material they see fit. Conspiracy theorists have exploited the speed with which the vaccines were developed to make all kinds of claims, many of which sound more believable than movement-tracking microchips.

Rather than reaching for statistics and talking about clinical trials, Dr. Adamson tries to meet concerned patients and friends with understanding and straightforwardness.

Developing most vaccines takes years, and the level of evidence that the Food and Drug Administration relied on to issue an emergency use authorization for the Pfizer-BioNTech and Moderna vaccines is lower than it requires for full authorization. But the Covid-19 vaccines available now are the product of unprecedented scientific concentration and government funding for research.

While those two highly effective F.D.A.-endorsed vaccines have been rigorously tested, however, it’s also true that we have no empirical evidence of their potential long-term impacts, because the disease hasn’t been around long enough. But experts are optimistic. “Based on our experience, it’s likely that it’s safe,” he said.

People of color have poignant historical reasons to be concerned about the government proactively offering them a vaccine. The legacy of medical experimentation on Black people in America stretches far beyond the infamous Tuskegee Syphilis Study.

“Black people don’t want to be treated like guinea pigs,” Dr. Adamson said, “because they’ve been treated like guinea pigs so many times before.”

Be cautious with information you immediately agree with.

Some false information is the product of misunderstanding, but a significant amount of the untrue things you might see online originated with people who intended to mislead. Successful disinformation is designed to play on your emotions. It’s easy to digest and often highly visual, provoking quick, often unthinking reaction. Ms. Muldoon said that moment — the moment when you quickly read something and it confirms your existing biases — is the one to be most wary of. “That’s when we stop thinking,” she said.

Hearing a misleading statistic like the widely circulated rumor that 99 percent of people survive Covid-19 might give some people hope that the pandemic will be over soon, or make them angry that they’ve spent the past year wearing a mask or cooped up inside. But “it’s super important to fact-check yourself,” Ms. Muldoon said. That means reaching outside your bubble for information — especially if that bubble is regularly on social media.

Try to choose your information sources wisely.

A lot of false information isn’t based on factual-sounding statements — it’s based on opinions and interpretations, said Peter Adams, senior vice president of education at the News Literacy Project.

As we all know, social media is rife with people ready to give advice. If your house flooded, you probably wouldn’t trust an amateur plumber on Facebook who suggests fixing your pipes with an herbal supplement. But when it comes to health, a lot of people do just that. A major form of false information Mr. Adams sees is “based on user-generated social media posts,” he said.

Avoid “doomscrolling” for information: In other words, don’t just sit in front of a social media feed full of alarming (and questionable) information and let it freak you out. When it comes to health advice, boring is better. Sources you had heard of before the pandemic started — like the Centers for Disease Control, fact-checking websites like Snopes, or even your local doctor’s office — and ones that regularly deliver the same kinds of routine advice (stay home, socialize cautiously, wear a mask) are the best sources of information.

Sources that make confusing, scary, hard-to-track claims that change quickly are probably not reliable. If you see a claim that confuses you, Ms. Muldoon suggests checking other trusted sources to see if they echo the information.

Even if you’re reading a trusted source, Ms. Muldoon emphasizes it’s important to make sure the information is current. We’ve been able to learn a lot more about Covid-19 in the past year, and that knowledge is still adjusting.

Don’t treat your Facebook friends like a trusted source.

During this pandemic, spreaders of misinformation have targeted people by using everything from printed newsletters to viral videos. But you’re most likely, said Mr. Adams, to encounter false information when it’s shared by people you know and care about — even if they’re doing it accidentally. Spreaders of false information are relying on that fact.

It might be tempting to argue with the people you care about who believe this false information and help them see reason. But trying to rebut each point isn’t a useful approach, said Sandra Crouse Quinn, a University of Maryland professor of public health who studies false information about vaccines.

Instead, Dr. Quinn suggested being a good digital citizen and trying to proactively share factual information from your own feed. If you choose to engage with other people who might be falling prey to false information, listen to their concerns, she said. Ask people what they think they’ve learned and ask them what they’re worried about. People who feel heard are more likely to be open to having a conversation about an issue they care about.

Don’t be afraid to change your mind.

“We all fall for bad information sometimes,” Ms. Muldoon said. Maybe you once believed wearing a mask to the grocery store would cause your oxygen levels to drop, but research has changed your mind. It’s important to be able to acknowledge when that happens, instead of doubling down on the bad information because of a need to be right.

When you encounter misinformation remember that it exists for the benefit of the misinformer, not to help you — no matter how it’s framed. Some individuals who share or create false information “are just looking for prominence online,” said Mr. Adams. “They’re looking for attention, likes and shares.” Others have been seduced by larger conspiracy theories with long histories, like the anti-vaccine movement, and may genuinely believe they are trying to help.

Ms. Muldoon said stepping away from the Covid-19 news cycle is a healthy and necessary step to take in protecting yourself from the ravages of the infodemic, and it won’t increase your pandemic risk. “The basics of what we need to do aren’t really changing,” she said. Stay at home, social distance, wear your mask, wash your hands and, when it’s your turn, get vaccinated. And instead of trawling social media for Covid-19 information, maybe just read a book.


Kat Eschner is a freelance science and business journalist who lives in Toronto.

C.D.C. Draws Up a Blueprint for Reopening Schools

C.D.C. Draws Up a Blueprint for Reopening Schools

Amid an acrid national controversy, the agency proposed detailed criteria for returning students to classrooms.

Students returning to P.S. 189 in Brooklyn in December, when New York City reopened its schools after rising infection rates had forced a closure.
Students returning to P.S. 189 in Brooklyn in December, when New York City reopened its schools after rising infection rates had forced a closure.Credit…Victor J. Blue for The New York Times
  • Feb. 12, 2021, 2:14 p.m. ET

The Centers for Disease Control and Prevention on Friday urged that K-12 schools be reopened and offered a comprehensive science-based plan for doing so speedily, an effort to resolve an urgent debate roiling in communities across the nation.

The new guidelines highlight the growing body of evidence that schools can openly safely if they put in effect layered mitigation measures. The agency said that even when students lived in communities with high transmission rates, elementary students could receive at least some in-person instruction safely.

And middle and high school students, the agency said, could attend school safely at most lower levels of community transmission — or even at higher levels, if schools put into effect weekly testing of staff and students to identify asymptomatic infections.

“CDC’s operational strategy is grounded in science and the best available evidence,” Dr. Rochelle Walensky, director of the C.D.C., said on Friday in a call with reporters.

The guidelines arrive in the middle of a debate that is already highly fraught. Some parents whose schools remain closed are becoming increasingly frustrated, and public school enrollment has declined in many districts across the country. Education and civil rights leaders are despairing about the harms being done to children who have not been in classrooms for nearly a year.

And teachers’ unions in some places are fighting against reopening schools before teachers can be fully vaccinated.

The Biden administration has made a high priority of returning children to classrooms, and the new recommendations try to carve a middle ground between school officials as well as some parents who are eager to see a resumption of in-person learning and powerful teachers’ unions resisting a return to school settings that they regard as unsafe amid the coronavirus pandemic.

Whether the guidelines will persuade powerful teachers’ unions — allies of Mr. Biden — to support teachers returning to classrooms remains to be seen. In advice that may be disappointing to some unions, the document states that, while teachers should be vaccinated as quickly as possible, teachers do not need to be vaccinated before schools can reopen.

The document embraces the often-repeated mantra that schools should be the last settings to close in a community and the first to reopen. But that has been followed nowhere in the country, and these guidelines have no power to force communities where transmission remains high to take steps, such as closing nonessential businesses, to decrease it.

As a result, some teachers’ unions will continue to argue that the overall environment remains unsafe to return to in-person classrooms.

A majority of districts in the country are offering at least some in-person learning, and about half of the nation’s students are learning in classrooms. But there are stark disparities in who has access to in-person instruction, with urban districts, which serve mostly poor, nonwhite children, more likely to be closed than nonurban ones.

Those are some of the places where education experts are most concerned about the consequences of students being out of school for such a prolonged period. There is growing evidence that some students who are learning remotely are falling significantly behind academically.

And, while data are still very limited, many doctors and mental health experts report seeing unusually high numbers of children and adolescents who are depressed, anxious or experiencing other mental health issues.

At the same time, many parents in urban districts, particularly poor and nonwhite parents, remain hesitant to send their children back to school even if given the option, out of fear that their children can get sick and possibly bring home the virus.

Schools have reopened partially or are starting to reopen in New York City, Chicago, Boston and other cities. But conflict between elected officials who support reopening and teachers’ unions seems likely to continue in places like Los Angeles, San Francisco and Portland, despite the new guidelines.

School district leaders have long asked for clearer guidelines from the federal government on how they should make decisions during the pandemic. The C.D.C.’s advice comes as a relief to many experts who have been frustrated at the low priority given to schools in local reopening plans.

“It’s not saying if you open schools again,” said Helen Jenkins, an infectious disease expert at Boston University and an adviser to the public schools district in Cambridge, Mass. “It’s saying, ‘You are going to open schools again, and this is how to do it,’ which I appreciate.”

The agency’s approach struck the right balance between the risks and the benefits of in-person instruction, said Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.

“We have accumulated a tremendous amount of harms from not having schools open,” Dr. Nuzzo said. “This document is important in trying to couch the risks in relation to those harms, and try to paint a path forward.”

The C.D.C. encouraged elementary schools to remain open regardless of virus levels in the surrounding community, pointing to evidence that young students are least likely to be infected or to spread the virus. Middle schools and high schools should switch to virtual learning only when community transmission of the coronavirus reaches the highest level, the agency said.

The agency also prioritized in-person instruction over extracurricular activities like sports and school events. In an outbreak, these activities should be curtailed before classrooms are closed, officials said.

Some experts raised concerns about the strategy.

Most school districts are in communities where viral transmission is already at or close to levels that the agency has deemed to be the highest risk, for example. Yet many have kept schools open without experiencing outbreaks of the virus.

“Most of the United States is sending their kids to school at above that cutoff,” said Dr. Jacqueline Grupp-Phelan, chief of pediatric emergency medicine at the University of California, San Francisco. “I’m not sure it’s going to make an impact on them, because they’re doing it and they’ve done it safely.”

Teachers and supporters demonstrating this month outside Samuel Gompers Public School in Philadelphia. Notably absent from the C.D.C. guidance are recommendations on improving ventilation in schools.
Teachers and supporters demonstrating this month outside Samuel Gompers Public School in Philadelphia. Notably absent from the C.D.C. guidance are recommendations on improving ventilation in schools.Credit…Matt Rourke/Associated Press
Cecilia Krizmanich, left, a teacher at Joyce Kilmer Elementary in Chicago, helped set up Marvin Araujo-Avilas’s computer on the first day of in-person classes on Thursday. Only two students showed up. Credit…Taylor Glascock for The New York Times

Notably absent from the agency’s guidance were recommendations on improving ventilation in schools, an important safeguard now that the coronavirus is known to be carried aloft in tiny airborne particles.

In one short paragraph, the C.D.C. suggested that schools open windows and doors to increase circulation, but said they should not be opened “if doing so poses a safety risk or a health risk.”

“C.D.C. gives lip service to ventilation in its report, and you have to search to find it,” said Joseph Allen, an expert on building safety at the Harvard T.H. Chan School of Public Health in Boston. “It’s not as prominent as it should be.”

The section on ventilation does link to more information online. But all of that is buried, relative to a misguided emphasis on cleaning surfaces like outdoor playground equipment, said Linsey Marr, an expert in airborne transmission of viruses at Virginia Tech.

“I think the balance is incorrect in putting so much emphasis on cleaning surfaces and almost no emphasis on cleaning the air, given what we know about how the virus spreads,” she said.

Ideally, the C.D.C. should also have mentioned high-quality masks or double-masking, Dr. Allen said. (The agency on Thursday released new advice for masking that included the use of two masks at once.)

Other preventive measures the C.D.C. recommended for schools are those it has previously endorsed: universal masking of staff and students; physical distancing; hand-washing and hygiene; cleaning; and contact tracing, in combination with isolation for those who have tested positive and quarantine for those who have been exposed to the virus.

The agency advised that schools refer all symptomatic students, teachers, staff and close contacts for diagnostic testing, and that schools put in place routine weekly testing of students and staff, except when community transmission is low. But the expense and logistics of widespread screening would be a heavy burden for school districts.

The C.D.C. skated lightly over physical distancing. “The agency’s previous recommendation for distancing suggested that schools have students attend on alternating schedules, in order to reduce the number of students in classrooms and hallways.”

The new guidance instead says schools should put in effect physical distancing “to the greatest extent possible,” but requires it only when community transmission of the virus is high. The softer emphasis makes the guidelines more feasible for school districts to follow, Dr. Nuzzo said.

“A lot of communities have pursued hybrid approaches, or in some cases just not opened, because they haven’t been able to figure out that spacing issue,” she said. The guidelines give the impression that maintaining at least six feet of distance between students is ideal, “but the whole attempt to bring kids back to school doesn’t have to break down over that,” she added.

The six-feet rule has been embraced as an orthodoxy, however, by many educators. Becky Pringle, president of the National Education Association, the country’s largest teachers union, said there should be no wiggle room on physical distancing or other mitigation strategies.

A socially distanced gym class in Provo, Utah.Credit…George Frey/Getty Images
A student entered Joyce Kilmer Elementary in Chicago, where schools are reopening after protracted disagreements with the teachers’ union.Credit…Taylor Glascock for The New York Times

“We need detailed guidance from the C.D.C. that doesn’t leave room for political games,” she said. “This is an airborne disease. Masks must be mandated, social distancing must be in place and proper ventilation is a must.”

As it had previously, the C.D.C. recommended using two measures to determine the risk of transmission in the community: the total number of new cases per 100,000 people, and the percentage of positive test results over the previous seven days.

The agency established four risk levels whose thresholds do not significantly differ from previous recommendations, except that the data are evaluated over seven days instead of 14 — a change that may allow schools to respond more quickly to shifting virus prevalence in their communities.

Dr. Jenkins of Boston University said the percentage of positive tests can vary with how much testing a community is doing. And the highest levels of community spread defined by the agency — 10 percent positivity, and 100 cases per 100,000 people over the previous seven days — are too conservative, she and other experts said.

“I do worry that there might be an impact on unnecessarily delaying the opening for the middle- and high school students,” said Dr. Grupp-Phelan of the University of California, San Francisco.

She added that her hospital, in a region where most middle- and high schools are closed, had seen large increases in adolescents who were suicidal or had developed eating disorders.

President Biden has pledged to open the majority of K-8 schools within the first 100 days of his administration. But on Wednesday, the White House press secretary, Jen Psaki, said that the president had been referring to in-person teaching “at least one day a week.”

That goal is already in reach: A majority of districts are offering at least some in-person learning, and about half the nation’s students are reporting to classrooms. The divide often falls along political lines. Conservative areas are likely to have open schools, while in liberal cities and suburbs, where teachers’ unions are influential, schools are more likely to be operating remotely.

Many districts, particularly ones in the South and the middle of the country, have offered fully in-person instruction for some or all grades at times when virus levels have risen far above what the C.D.C. says is advisable.

According to the agency’s guidelines, the approximately one-third of schools that remain entirely virtual may be too cautious.

Students received hand sanitizer before entering P.S. 316 in Brooklyn in December.Credit…Anna Watts for The New York Times
Temperature checks at Joyce Kilmer Elementary in Chicago on Thursday.Credit…Taylor Glascock for The New York Times

If the new recommendations had been in place last fall, for example, San Francisco could have opened all of its schools for fully in-person instruction in mid-September (although the city may have chosen to close middle- and high schools as cases began climbing in November).

Today, according to the guidelines, San Francisco could open elementary schools in a hybrid mode, and is close to being able to open middle- and high schools in a hybrid mode.

Instead the city’s schools have been shuttered since the pandemic began, and the district has agreed to far more restrictive reopening standards with its union. Officials have set no date for bringing young children back to school, and have said they do not expect most middle- and high school students to return in person this year.

Rebecca Bodenheimer is a mother of a third-grader in Oakland, Calif., and an organizer of a parent group that has been pushing the city’s school district, which is currently all virtual, to set a date for reopening.

The C.D.C.’s guidelines sounded reasonable, Ms. Bodenheimer said. But she was not sure they would sway a debate that was emotional for many.

“The research and data have been piling up about the fact that schools can open safely, and those people who are just only operating on unfounded fear — I don’t see a lot of them coming around,” she said.

Some local unions continue to fight reopening efforts, demanding that teachers be vaccinated before returning to classrooms. The new guidance recommended that states immunize teachers in early phases of the rollout but said access to vaccines should “nevertheless not be considered a condition for reopening schools for in-person instruction.”

Vaccinating teachers is very effective at cutting down cases in both teachers and students in a model of transmission in high schools, said Carl Bergstrom, an infectious diseases expert at the University of Washington in Seattle. “It should be an absolute priority,” he said.

Still, he added, “I can certainly see why they chose not to make it a prerequisite, because it may not be something that can be done in time to have schools open.”

Teachers’ unions have also asked for stringent protections regarding hygiene and air quality inside school buildings.

In Boston, for example, air quality was a major point of contention in reopening negotiations between the school district and teachers’ union. The agreement that paved the way to students returning to schools called for air purifiers in classrooms and a system for testing and reporting air quality data.

Ms. Pringle, the union president, said her members continue to be concerned about aging school buildings that do not include modern ventilation systems. Those schools were more likely to be located in lower-income and nonwhite communities hit hardest by the pandemic.

Many teachers have “no trust” that school administrators will put strong virus safety measures in place or will be given the funding to do so, Ms. Pringle said: “That’s why you see educators rising up across the country and saying, ‘At least give us the vaccine.’”

Dental Practices Change in the Covid Era

Less Drilling, Less Germ Spray: Dentistry Adapts to the Covid Era

The pandemic has forced dentists and hygienists to change some of the methods for maintaining good oral hygiene, to protect patients as well as themselves.

Dr. Todd Kandl performs a root canal at his dentistry practice in East Stroudsburg, Pa., with extra Covid precautions, including an external oral air scrubber, an oral dental dam on the patient and extra layers of protective clothing.
Dr. Todd Kandl performs a root canal at his dentistry practice in East Stroudsburg, Pa., with extra Covid precautions, including an external oral air scrubber, an oral dental dam on the patient and extra layers of protective clothing.Credit…Jonno Rattman for The New York Times

  • Feb. 9, 2021, 2:30 a.m. ET

Ann Enkoji normally enjoys seeing her dental hygienist, but when her dentist’s office in Santa Monica, Calif., canceled her cleaning visit last spring, she felt relieved.

She had been wary of keeping the appointment anyway, worried about someone else’s fingers and instruments exploring her mouth at a time when more than 25,000 Americans were contracting the coronavirus daily.

“It’s just too up close in that mouth-nasal region,” said Ms. Enkoji, 70, a marketing design consultant based in Santa Monica.

When she returned to her dentist’s office in September for a cleaning, she was asked to wash her hands and use an antimicrobial mouth rinse, steps that federal health guidance said might help curb the spread of germs in aerosol and splatter during treatment.

Without a doubt, dentistry is among the more intimate health professions. Patients must keep their mouths wide open as dentists and hygienists poke around inside with mirrors, scalers, probes and, until recently, those cringe-inducing drills.

Such drills and other power equipment, including ultrasonic scalers and air polishers, can produce suspended droplets or aerosol spray that may hang in the air, potentially carrying the virus that could endanger patients and staff.

Today, dental offices operate in a markedly different way than they did pre-pandemic. Since reopening in May and June, they have been following federal guidelines and industry group recommendations aimed at curtailing the spread of Covid.

Los Angeles County, where Ms. Enkoji lives, passed 1.4 million in cases, and New York City has reported more than half a million cases.

And while vaccination offers fresh promise, there are new worries about more contagious variants of the virus as well as a months-long timetable for rolling out the vaccines to the general public.

Many dental offices have stayed open in recent months, with dentists and hygienists geared up in face shields, masks, gowns, gloves and hair covers resembling shower caps. They have set aside aerosol-spewing power equipment, and hygienists instead rely on traditional hand tools to remove patients’ built-up plaque and tartar.

Under the new practices, patients typically get called a few days before visits and are asked if they have any Covid symptoms. They may be told to wait in their cars until they can be seen. Their temperatures may be taken before entering a dental office, and they have to wear masks, except during treatment, all measures recommended by the U.S. Centers for Disease Control and Prevention.

Dental offices also look different now. Many dentists are allowing only one patient in the office at a time. At Exceptional Dentistry on Staten Island, the waiting area is bereft of magazines, and plexiglass shields have been installed at the front desk, said Dr. Craig Ratner, owner of the office in the Tottenville neighborhood.

Donning a face shield over his cap, Dr. Kandl wears two masks, a surgical gown and dental loupes.Credit…Jonno Rattman for The New York Times
A dental dam is used to isolate a work area and to cover a patient’s mouth.Credit…Jonno Rattman for The New York Times

And visits may last longer, because scaling by hand is more laborious than applying ultrasonic scalers, and because some patients have built-up tartar, stains and plaque on their teeth stemming from pandemic-related gaps in visits, said Dr. Ratner, who is president of the New York State Dental Association.

“It’s unfortunate, but understandable,” he said.

This revolution in dental protective gear has been compared to the one that accompanied the HIV/AIDS pandemic, when many dental workers began wearing gloves and masks for the first time, according to an article in the journal JDR Clinical & Translational Research.

“Dentistry has changed — it’s incredible how it has changed over the last few months,” said Dr. Donald L. Chi, a pediatric dentist and professor of oral health sciences and health services at the University of Washington.

Covid-19 had barely touched the United States early last February when Dr. William V. Giannobile, dean and professor at the Harvard School of Dental Medicine in Boston, heard from a counterpart in Wuhan, China.

The dean of the dental school in Wuhan, where the coronavirus was first been reported on New Year’s Eve in 2019, asked Dr. Giannobile if he would help get his team’s findings republished in the United States.

The authors of the article, which would appear in The Journal of Dental Research, laid out basic safety measures that would later be adopted by thousands of U.S. dentists.

“They showed that the provision of dental care is safe and that guidelines could be put in place to triage patients and provide dental care,” Dr. Giannobile said.

Those guidelines include not only the now-ubiquitous use of staff protective gear, but also pre-visit questions and temperature checks and patients’ use of masks. And the Wuhan researchers stated that “in areas where Covid-19 spreads, nonemergency dental practices should be postponed” — advice endorsed early last year by the C.D.C. and the American Dental Association.

The springtime shuttering of dental businesses caused a lot of hardship for many dental practices. Only 3 percent of those offices in the United States stayed open in March and April, and layoffs and furloughs led to the disappearance of more than half of dental-office jobs, said Marko Vujicic, the chief economist for the A.D.A.

“This was an unprecedented event in dentistry,” Mr. Vujicic said. But when doors swung open later in the spring, the number of patients soared.

His association has been seeking permission to provide tests for the virus nationwide, as well as to administer Covid vaccines. Dentists were allowed to administer the vaccine in 20 states, including California, Connecticut, New Jersey and New York, A.D.A. research showed.

Dr. Donald L. Chi, who practices at the Odessa Children’s Clinic in Seattle, says that one way that he avoids drilling — and unnecessarily spreading the virus — is to place silver diamine fluoride on a child’s baby tooth to prevent a cavity from growing.
Dr. Donald L. Chi, who practices at the Odessa Children’s Clinic in Seattle, says that one way that he avoids drilling — and unnecessarily spreading the virus — is to place silver diamine fluoride on a child’s baby tooth to prevent a cavity from growing.Credit…Jovelle Tamayo for The New York Times

Dentists rank high on the priority lists for those eligible to get the vaccine, with Phase 1a status in 40 states. The C.D.C. recommends that dental hygienists and assistants also be included on the vaccine priority list.

In New York City, the College of Dentistry at New York University suspended in-person visits last winter, but resumed urgent cases in late June. Since then, it has treated more than 700 patients a day, said Elyse J. Bloom, associate dean of the college. And its mandatory virus testing for students and members of the faculty and the staff has helped keep the college’s count of positive cases significantly lower than that of New York City over all, she said.

Fear of job losses has rippled through the industry.

“This was a very frightening time for many individuals,” said JoAnn Gurenlian, a professor of dental hygiene at Idaho State University who heads a return-to-work task force for the American Dental Hygienists Association.

More than half of dental hygienists, dental therapists and oral health specialists reported that they were not working in a June 2020 survey conducted by the International Federation of Dental Hygienists. Half said they were deeply concerned that they would not have enough personal protective gear to treat patients.

Patients, too, have been anxious. Some dentists have found themselves treating stressed clients who were grinding their teeth in their sleep and needed devices to prevent chips or fractures.

“Honestly, I’ve made a lot of night guards,” said Dr. Todd C. Kandl, who has spent 13 years building up his family practice with a staff of eight in East Stroudsburg, Pa., tucked away in the Poconos.

Forced to close the practice in mid-March, Dr. Kandl received a federal loan that allowed him to reopen on June 1. In between, he tried to diagnose patients’ conditions over the phone, he said. Now, most of his patients have come back.

He and his staff follow C.D.C. guidelines by putting on a clean gown for each patient and changing it afterward. They launder all gowns at the office.

He has installed a number of the upgrades recommended by the C.D.C., including high-efficiency particulate air, or HEPA, filter units to trap fine particles. And he purchased several suction systems that remove droplets and aerosols, as well as ultraviolet light to help sanitize.

Dr. Kandl also chose to discontinue use of nitrous oxide, a gas used to mildly sedate and relax anxious dental patients. In the past, he rarely used the gas, but amid the Covid-19 outbreak, he grew concerned about his system, an older type that wasn’t worth the risk of exposing patients.

Lynn Uehara, 55, the business manager for a Hawaii family dental practice, said that island living had resulted in shipping problems to obtain the protective gear that her employees need.

“Our masks and gloves are being rationed by our main dental suppliers,” Mrs. Uehara said. Gowns ordered four months ago finally arrived. And prices are soaring. “We used to pay about $15 for a box of gloves. Now they are charging us $40 to $50 a box.”

But like other dental workers, she is now a veteran of uncertainty. If the lack of protective gear means reducing the number of patients, “then that’s what we will do,” she said.

Dental tools await sterilization at Dr. Kandl’s office.Credit…Jonno Rattman for The New York Times
A U.V. sterilizer in Dr. Kandl’s office.Credit…Jonno Rattman for The New York Times

The Uehara family has offices in Honolulu on Oahu and in Hilo, on the Big Island of Hawaii. The pandemic lockdowns hurt its practices. Family members commute between the two islands by commercial jet, posing another risk.

The reopening went slowly, but patients have returned. “I’ve heard the sound of laughter back in the office,” Mrs. Uehara said.

A surge in coronavirus cases among children has also posed challenges for pediatric dentists.

In early December, the C.D.C. strongly endorsed school-based programs in which dentists apply thin coatings called sealants on the back teeth of children in third through fifth grades. Such sealants are especially helpful for children at risk of cavities and for children whose families can’t afford private dentists, the agency said.

Dr. Chi, the pediatric dentist and University of Washington professor, said that dentistry was turning to more conservative methods of dealing with tooth decay now that some drills and tools might heighten the risk of contagion.

Dr. Chi, who practices at the Odessa Children’s Clinic in Seattle, said that one way that he avoided drilling was to place silver diamine fluoride on a child’s baby tooth to prevent a cavity from growing.

He can also select stainless steel crowns to block the growth of a cavity. Applying such crowns normally requires numbing the tooth, using a drill to remove decay and reshape the tooth, and then installing the crown.

A more conservative approach: placing a crown directly on the baby tooth without removing decay or reshaping. Evidence suggests that it is as effective as the traditional approach, takes less time and is more cost-effective, Dr. Chi said.

“Covid has really encouraged dentists to look at all the options you have to treat dental disease,” he said.

Some dentists, however, may choose to leave the profession. The A.D.A. conducted a survey asking dentists how they would react if their patient visits remained the same for several months.

“Our data show that 40 percent of dentists 65 and older would seriously consider retiring in the coming months if patient volume remains at what it is today,” Dr. Vujicic said.

Over time, though, some patients have learned to adjust.

Enid Stein of Staten Island has visited Dr. Ratner’s practice five times since it reopened, for implant surgery and new crowns. A self-described germaphobe who carries alcohol spray in her pocketbook, she brought her own pen to pay by check.

“I’m done, thank God,” she said. “Not that I don’t mind seeing him and all the girls in the office, but I’m in good shape.”

Is Your Super Bowl Party a Superspreader Event?

Super Bowl Party or Superspreader Event?

Experts offer tips on how to stay safe. For one, don’t plan on shouting or cheering with your friends.

Credit…Getty Images
Christina Caron

  • Feb. 4, 2021, 5:00 a.m. ET

For millions of football fans, Super Bowl Sunday has become the equivalent of a major holiday. It’s like Thanksgiving, only with way more shouting, drinking, hugging and dipping into shared snacks. But this year, public health experts are urging everyone to tone it down and take special precautions when watching the big game.

“I know that no one wants to be the guy that got hospitalized or died because of the Super Bowl,” said Dr. Joshua Barocas, an infectious diseases physician at Boston Medical Center. “With the highly transmissible variants around and a largely unvaccinated public, we are all at high risk.”

Last year, gatherings to watch Lakers games during the N.B.A. finals were believed to have accelerated the virus’s surge in Southern California, officials in Los Angeles said. And after the fall and winter holidays, coronavirus cases spiked in some parts of the country as people skirted public health guidelines to celebrate with one another.

Now, after what has been nearly a year of social distancing, Sunday’s matchup between the Tampa Bay Buccaneers and the Kansas City Chiefs is beckoning.

“It’s not like Thanksgiving where millions and millions are traveling, but will we see cases linked to Super Bowl parties at people’s homes? I think most definitely yes,” said Joseph G. Allen, an expert on indoor environmental quality at the Harvard T.H. Chan School of Public Health.

According to a recent Seton Hall University survey of more than 1,500 adults across the country, 58 percent said that they will watch the Super Bowl this year. And of those, a quarter are planning to do so with people from outside their households. Another study, from the National Retail Federation, found that 28 percent of those who intend to watch the Super Bowl are planning to either host or attend a party, or watch the game at a bar.

Here are three ways that fans might watch the game this Sunday, ranked from least to most risky, and some guidance from experts on how to stay safe.

Least Risky

With household members

The experts we spoke with echoed recommendations from the Centers for Disease Control and Prevention that the safest way to watch the game is at home with only the people you live with. And in recent surveys, most Super Bowl fans have indicated that this is exactly what they’ll do.

Gathering with people from outside your household is taking a risk, Dr. Allen said.

You can still include other family and friends virtually. The C.D.C. recommends connecting with others by sharing recipes, starting text chains or hosting a party online. You can use Zoom, Google Hangouts or streaming services with virtual group watch features.

Sandra Albrecht, an assistant professor of epidemiology at the Columbia University Mailman School of Public Health in New York City, is planning to attend a watch party on Zoom.

“I’m a huge football fan, and I watch the Super Bowl every year,” she said. “But this is one year where my family and I will forgo any in-person parties and will instead enjoy the game in the remote company of family and friends.”

Another potential benefit of sticking with only the people in your household: It can be less stressful. You don’t have to worry as much about who’s double dipping in the salsa or if the windows are open wide enough.

More Risky

With non-household members — outdoors

When people talk, shout, cheer or laugh outdoors, the tiny droplets of saliva that come out of their mouths are more rapidly dispersed into the environment and become more diluted. That means that when you’re outdoors with others, you’ll be less likely to get infected than if you were indoors with the same group of people.

But the risk is not zero. If you decide to attend an outdoor gathering with people from other households, it’s still important to wear masks the entire time (except when eating) and to stay at least six feet apart, the experts said.

Erin Jackson, 38, and her husband invited 11 guests to watch the Super Bowl on a 100-inch screen in their large backyard in Chapel Hill, N.C.

“We also had a lot of discussions over whether to do anything at all, because we are terrified about not being cautious,” Ms. Jackson said.

So they came up with a few rules: Everyone has to bring their own snacks, the house will be off limits and the chairs will be placed at least six feet apart.

So far, nobody has committed to showing up.

“It felt like an opportunity to reach out to our relatively small group of friends here and let them know we were thinking about them and that we wanted to be spending time with them,” Ms. Jackson said. But, she added, they also recognized that “probably very few would take us up on it.”

If you decide to go to an outdoor venue, like a bar or a restaurant, the C.D.C. recommends calling ahead of time to find out which (if any) precautions they have taken.

Most Risky

With non-household members — indoors

Each of the experts we spoke with, along with the C.D.C., strongly advised against gathering indoors with people you don’t live with. Some evidence suggests that small gatherings have driven virus transmission in certain areas. In December, for example, New York announced that its contact tracing data showed that 70 percent of new Covid-19 cases originated from households and small gatherings.

Even so, meeting indoors might be tempting for fans who live in parts of the country where temperatures are expected to dip below freezing on Sunday.

But if people snack inside someone’s home and talk loudly throughout the game, “such conditions are ideal for the spread of the coronavirus,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who studies viruses in the air. “People can spread the disease without feeling any symptoms.”

If you decide to take the risk, make sure to wear a mask at all times and stay at least six feet from others. And if you want to eat and drink, “do it outside and distanced from others,” Dr. Marr said.

If you’re the host of the party, keep the guest list as small as you can, ideally just one or two people from outside your household. Alternatively, if you’ve been invited to a party, try to find out how many people will be attending and what size party you would be most comfortable with. Don’t feel pressured to stay for the entire game; Dr. Marr suggested dropping by for the length of a quarter to diminish your exposure to others.

Finally, make sure the windows and doors are cracked open. “Even just a few inches can make a big difference to improve ventilation,” Dr. Marr said.

More Ways to Protect Yourself and Others

If you gather with others, the C.D.C. says there are general precautions you can take to stay as safe as possible. Try to avoid shouting, cheering loudly or singing, which can increase the amount of respiratory droplets in the air. Instead, clap, stomp your feet or use noisemakers.

The C.D.C. also recommends bringing your own food, drinks, plates, cups and utensils.

If people drink too much alcohol, they might let their guard down or relax the rules. So be mindful of how the people around you are behaving and control how much you’re consuming so that you can keep a clear head.

Finally, don’t get lulled into a false sense of security. Even if everyone has been fully vaccinated, it can take a week or two after the second shot to build peak protection. And while vaccinated people are less likely to get severe Covid-19, experts don’t yet know if they can still spread the virus to others, said Dr. Asaf Bitton, a primary care physician at Brigham and Women’s Hospital who specializes in public health.

Finally, remember that negative Covid tests are no guarantee of safety. The virus may not have been detectable on the day of the test or the result could be a false negative.

“One test at one point in time is just not going to give you the clarity that you need to know that it’s safe for your groups to get together,” Dr. Bitton said.

Helping a Teen Who Is Angry About House Rules on Covid

Helping a Teen Who Is Angry About House Rules on Covid

Our grandson’s friends don’t socialize safely, so we don’t want him to see them. How do we keep his anger about it from causing chaos in our home?

Credit…Chloe Cushman
Lisa Damour

  • Jan. 29, 2021, 5:00 a.m. ET

Our Adolescence columnist, the psychologist Lisa Damour, responds to a reader’s question. The question has been edited.

[To submit a question, email AskDrDamour@nytimes.com.]

Q. We are having an extremely difficult time with our 15-year-old grandson, who lives with us. He has finally found friends after struggling socially and wants to spend time with them, but they do not social distance or wear masks. Some of their families are not true believers in this pandemic. It is absolute chaos at our house because of him fighting to be able to do things. He says he is tired of Covid, because while he stays in, most of his friends do not and go about their lives like nothing has changed. He is angry and depressed and we are at a loss as to what to do.

A. You and your grandson are in a heartbreaking predicament for which there are no complete or satisfying solutions. I cannot tell you how much I wish this weren’t true. Above all, I want to acknowledge the painful reality of the circumstances you describe.

Even though there are no perfect remedies, it may still be possible to improve the situation at least a little bit. First, let’s note that you are contending with two distinct, albeit related, challenges. One is that the pandemic has uprooted your grandson’s budding social life. The other is that his perfectly warranted distress about falling out of touch with his new friends has ruptured his relationships at home. On the first front, you may be hard-pressed to offer your grandson more social opportunities than you already have. On the second front, however, there may be ways to repair your connection with your isolated teenager, who needs loving support now more than ever.

Empathy, empathy, empathy is the place to start. The situation in which he finds himself is miserable and not of his creation. It may be true that he is acting out and upsetting everyone around him, and that many other young people find themselves in similar straits, and that we are starting to catch glimpses of the light at the end of the tunnel. Try not to let these factors sap your sympathy for your grandson. The adjustments that we have been asking adolescents to make, both in how they conduct their social lives and how they learn, take almost all of the fun out of being a teenager and have been in place for nearly a year. No amount of compassion for this is too much.

Without any other agenda, deliver to your grandson the message that you are deeply sorry that the pandemic has wreaked havoc on his social life. Tenderly communicate that you grasp how painful it must be to know that his friends are getting together without him. Let him know that you cannot believe that the pandemic has gone on for so long (roughly one-tenth of the lifetime that he likely remembers) and that you understand that for teenagers in particular, the support of family cannot make up for losing touch with friends.

Compassion won’t alter the lousy circumstances, but it can still help to relieve his emotional suffering. Feeling alone with psychological pain is a lot worse than believing that your distress is seen and validated. So, do all you can to help your grandson know that you are entirely on his team.

There’s another way to look at this that may help you to move toward a better relationship with your grandson: Recognize that he may be turning an intractable, internal battle — between his desire to see his friends and his knowledge that their way of socializing isn’t safe — into an external battle between him and you.

It’s not at all uncommon for teenagers to turn vexing personal dilemmas into fractious family fights. Imagine a (post-pandemic) teenager who both wants to go to a concert and also feels unnerved by its sketchy venue. She might seek relief from being at odds with herself by recruiting her parents to take up one side of the battle. Picking this fight would be as simple as wholeheartedly lobbying to go to the concert while rolling her eyes when her folks pose reasonable safety questions.

Try to ease your grandson away from this instinctive approach by warmly and sympathetically articulating his dilemma. “It’s really frustrating,” you might say, “that your friends are doing things in a way that makes it impossible for you to safely see them. I get why you’re so upset.” This might open the door for him to welcome you as a strategic ally. “We’ll do whatever we can to help you see your friends in a safe way. Can you take bike rides together or go throw a ball around outside? We’re happy to take the blame if you want to pin the need to be outdoors and wear masks on us. Just let us know if there’s anything you can think of that we might do to make this work.”

It’s possible, of course, that your grandson won’t like your suggestion or want to test the strength of his friendships. If so, there is something else you can try. New research in the journal Child Development has found that teenagers are better able to bear pandemic conditions when their families support their autonomy. Are there choices you can offer your grandson that have not been left to him before? Perhaps you can give him more say over how or where he studies, what he does with his leisure time, who controls the remote or anything else you can bring to the negotiating table. Own the limits of what you are offering. Acknowledge that getting to pick the dinner menu won’t fix things with his friends. But having some new freedoms at home might just help him feel better enough.

Hopefully, your efforts will lighten your grandson’s mood. If he remains unhappy no matter what you try, make an appointment with his health provider to have him evaluated for depression which, in teenagers, often comes across more as irritability than sadness.

You and your grandson are not alone in feeling painted into a terrible corner by the pandemic. Even with so much beyond our control, let’s not overlook the ways, however incremental, that we can comfort and support our teenagers.

This column does not constitute medical advice and is not a substitute for professional mental health advice, diagnosis or treatment. If you have concerns about your child’s well-being, consult a physician or mental health professional.


Yes, You Still Need to Wear a Mask

Personal Health

Yes, You Still Need to Wear a Mask

Short of a total lockdown, universal mask-wearing is the most effective way to slow the relentless rise in hospitalizations and deaths from Covid-19.

Credit…Gracia Lam
Jane E. Brody

  • Jan. 25, 2021, 5:00 a.m. ET

As a professional health writer and concerned citizen, the ache in my heart deepens with each new report of the devastation wrought by the novel coronavirus, the cause of immeasurable — and still increasing — personal and economic pain for people caught in its deadly spikes.

In a recent five-week period, 100,000 Americans died from complications of Covid-19, a toll that took the country four months to reach last spring.

My distress is magnified by the knowledge that it didn’t have to be this bad. One simple measure — consistent wearing of face coverings in public — could have helped to stem the agony. In December, the Centers for Disease Control and Prevention reiterated advice first given in July: “Wear a mask over your nose and mouth. Everyone should wear a mask in public settings and when around people who don’t live in your household, especially when other social distancing measures are difficult to maintain.”

Masks, the agency emphasized, protect both the wearer and those the wearer encounters in the course of daily life.

Now, with the emergence of a highly contagious variant of the virus and the chaotic attempts to distribute and administer vaccines to hundreds of millions of vulnerable Americans, short of a total lockdown, universal mask-wearing is the most effective way to slow the relentless rise in hospitalizations and deaths from Covid-19.

It will take many months to immunize everyone willing and able to get a Covid vaccine. Meanwhile, we’re facing another tsunami of deadly coronavirus infections as the new variant sweeps through swaths of still-unprotected millions.

As with many other measures not taken by the last administration to minimize the spread of Covid-19, mask-wearing was left up to the states to mandate and enforce. Masks became a political football, and the former president publicly ridiculed opponents who wore them. Some elected officials even made the ridiculous, baseless claim that masks not only don’t thwart the spread of the virus, they actually enhance it. I wonder if they also ignored parents and teachers who told them to cover their mouths when they coughed or sneezed.

I also wonder about the economic savvy of our former president and the governors who have resisted issuing mask mandates, some of whom got Covid-19 themselves yet clamored to open the economy. Goldman Sachs estimated last June that implementing a nationwide mask mandate could have a potential impact on the U.S. GDP of one trillion dollars.

Lately, as I await my second vaccine shot, I’ve become increasingly aware of how many people walk, run or cycle without a mask or, if they have a mask, wear it ineffectively. I’ve taken to speaking up more often: “Please wear your mask” or “The mask should cover your nose and mouth.” Among the ignorant responses: “I don’t need a mask when I’m outside,” “I already had Covid so I can’t get it again or give it to you,” and my favorite while walking on a four-foot-wide path, “I stay six feet away from people.”

Although six-foot social distancing is not totally arbitrary, it’s based on limited evidence among airline passengers and may not apply at all, for example, to the unmasked cyclists shouting to one another as they ride past me or to the heavy-breathing runners I pass.


Covid-19 Vaccines ›


Answers to Your Vaccine Questions

While the exact order of vaccine recipients may vary by state, most will likely put medical workers and residents of long-term care facilities first. If you want to understand how this decision is getting made, this article will help.

Life will return to normal only when society as a whole gains enough protection against the coronavirus. Once countries authorize a vaccine, they’ll only be able to vaccinate a few percent of their citizens at most in the first couple months. The unvaccinated majority will still remain vulnerable to getting infected. A growing number of coronavirus vaccines are showing robust protection against becoming sick. But it’s also possible for people to spread the virus without even knowing they’re infected because they experience only mild symptoms or none at all. Scientists don’t yet know if the vaccines also block the transmission of the coronavirus. So for the time being, even vaccinated people will need to wear masks, avoid indoor crowds, and so on. Once enough people get vaccinated, it will become very difficult for the coronavirus to find vulnerable people to infect. Depending on how quickly we as a society achieve that goal, life might start approaching something like normal by the fall 2021.

Yes, but not forever. The two vaccines that will potentially get authorized this month clearly protect people from getting sick with Covid-19. But the clinical trials that delivered these results were not designed to determine whether vaccinated people could still spread the coronavirus without developing symptoms. That remains a possibility. We know that people who are naturally infected by the coronavirus can spread it while they’re not experiencing any cough or other symptoms. Researchers will be intensely studying this question as the vaccines roll out. In the meantime, even vaccinated people will need to think of themselves as possible spreaders.

The Pfizer and BioNTech vaccine is delivered as a shot in the arm, like other typical vaccines. The injection won’t be any different from ones you’ve gotten before. Tens of thousands of people have already received the vaccines, and none of them have reported any serious health problems. But some of them have felt short-lived discomfort, including aches and flu-like symptoms that typically last a day. It’s possible that people may need to plan to take a day off work or school after the second shot. While these experiences aren’t pleasant, they are a good sign: they are the result of your own immune system encountering the vaccine and mounting a potent response that will provide long-lasting immunity.

No. The vaccines from Moderna and Pfizer use a genetic molecule to prime the immune system. That molecule, known as mRNA, is eventually destroyed by the body. The mRNA is packaged in an oily bubble that can fuse to a cell, allowing the molecule to slip in. The cell uses the mRNA to make proteins from the coronavirus, which can stimulate the immune system. At any moment, each of our cells may contain hundreds of thousands of mRNA molecules, which they produce in order to make proteins of their own. Once those proteins are made, our cells then shred the mRNA with special enzymes. The mRNA molecules our cells make can only survive a matter of minutes. The mRNA in vaccines is engineered to withstand the cell’s enzymes a bit longer, so that the cells can make extra virus proteins and prompt a stronger immune response. But the mRNA can only last for a few days at most before they are destroyed.

I’ve also heard a few people say, “I already got the vaccine, so I don’t need a mask.” This may be the most dangerous excuse of all. First, although the vaccines are very good, they’re not perfect, and chances are these vaccine recipients haven’t been checked for strong antibodies to the virus. Second, we don’t yet know if the vaccines, while highly effective in preventing sickness and death, will also prevent asymptomatic infection that can spread the virus to others.

As Jeremy Howard, a data scientist at the University of San Francisco, said of mask refusers: “How would you feel if you made your best friend sick, or killed your friend’s mother?”

Last February, after the World Health Organization, with no supporting data, advised against wearing a mask unless you were already sick, Mr. Howard amassed an international team of 19 scientists to review the evidence for mask-wearing, expecting to find “that masks were a waste of time,” he said in an interview. Instead, he said, the team found that “the data on the benefit of masks is really compelling.” The results of their exhaustive study were published recently in PNAS, the peer-reviewed Proceedings of the National Academy of Sciences.

Mr. Howard said that preliminary reports of their findings resulted “in all sorts of abuse, including death threats” from mask resisters. But that has not kept him from repeating that “wearing any kind of mask will greatly help to keep you from accidentally infecting others, which is important for the community and the economy. About half of coronavirus infections are spread by people who don’t know they’re sick, and the new variant is much more transmissible.”

A Chinese study found that the viral load in the upper respiratory tracts of infected people without symptoms can be just as high as those with symptoms, and simply talking and breathing can spread virus-laden droplets and aerosols. And because the virus resides in high amounts in the nose and throat, sneezing can spew an infectious cloud 10 or more times further than coughing.

Which brings me to the question of whether the face coverings most people use are sufficiently protective. I now know that the bandannas, exam masks and the slim neoprene masks I’ve been using for the last 11 months are better than nothing but not very good. They provide too many routes for virus-carrying particles to reach an unsuspecting nose or mouth.

I should have followed the advice my colleague Tara Parker-Pope offered months ago on upgrading your mask.

“Masks,” Mr. Howard said, “need a nose wire to provide a close fit and proper filtration material, like a nanofiber, that filters very small particles.”

He and his co-authors concluded that for most of us, KN95 masks, especially those with bands that fit around the head, are currently the best to prevent contracting and spreading the virus.

Another option is the KF94 mask or, if it’s not too uncomfortable, doubling up on masks for added protection.

KN95 masks meet foreign certification standards and are designed to filter out 95 percent of particles down to 0.3 microns in size. (The gold standard N95 masks, which meet U.S. certification standards, should be reserved for health care and emergency personnel who are most likely to interact with Covid-infected individuals.)

Powecom KN95 masks have an emergency use authorization from the Food and Drug Administration. I just ordered a packet of 11 on Amazon for $23.80 and I expect to be using them for many months after I’m vaccine-protected. I might still be able to transmit the virus and I want to set a good example for my fellow citizens.

What You Can Do to Avoid the New Coronavirus Variant Right Now

Ask Well

What You Can Do to Avoid the New Coronavirus Variant Right Now

It’s more contagious than the original and spreading quickly. Upgrade your mask and double down on precautions to protect yourself.

Credit…Getty Images
Tara Parker-Pope

  • Jan. 19, 2021Updated 3:44 p.m. ET

New variants of the coronavirus continue to emerge. But one in particular has caused concern in the United States because it’s so contagious and spreading fast. To avoid it, you’ll need to double down on the same pandemic precautions that have kept you safe so far.

The variant known as B.1.1.7., which was first identified in Britain, doesn’t appear to cause more severe disease, but it has the potential to infect an estimated 50 percent more people. The Centers for Disease Control and Prevention has predicted that this variant could become the dominant source of infection in the United States by March. Variants with the same mutation have been reported in Brazil and South Africa, and now scientists are studying whether a variant with a different mutation, and first found in Denmark, has caused a surge in cases in California.

The new variant spreading in the United States appears to latch onto our cells more efficiently. (You can find a detailed look inside the variant here.) The change suggests it could take less virus and less time in the same room with an infected person for someone to become ill. People infected with the variant may also shed larger quantities of virus, which increases the risk to people around them.

“The exact mechanism in which it’s more transmissible isn’t entirely known,” said Nathan D. Grubaugh, assistant professor and epidemiologist at the Yale School of Public Health. “It might just be that when you’re infected, you’re exhaling more infectious virus.”

So how do you avoid a more-contagious version of the coronavirus? I spoke with some of the leading virus and infectious disease experts about what makes the new variant so worrisome and what we can do about it. Here’s what they had to say.

How can I protect myself from the new coronavirus variant?

The variant spreads the same way the coronavirus has always spread. You’re most likely to contract the virus if you spend time in an enclosed space breathing the air of an infected person. The same things that have protected you from the original strain should help protect you from the variant, although you may need to be more rigorous. Wear a two- or three-layer mask. Don’t spend time indoors with people not from your household. Avoid crowds, and keep your distance. Wash your hands often, and avoid touching your face.

“The first thing I say to people is that it’s not a different virus. All the things we have learned about this virus still apply,” said Dr. Ashish K. Jha, dean of the Brown University School of Public Health. “It’s not like this variant is somehow magically spreading through other means. Anything risky under the normal strain just becomes riskier with the variant.”

And let’s face it, after months of pandemic living, many of us have become lax about our Covid safety precautions. Maybe you’ve let down your guard, and you’re spending time indoors and unmasked with trusted friends. Or perhaps you’ve been dining in restaurants or making more trips to the grocery store each week than you did at the start of lockdowns. The arrival of the variant means you should try to cut back on potential exposures where you can and double down on basic precautions for the next few months until you and the people around you get vaccinated.

“The more I hear about the new variants, the more concerned I am,” said Linsey Marr, professor of civil and environmental engineering at Virginia Tech and one of the world’s leading aerosol scientists. “I think there is no room for error or sloppiness in following precautions, whereas before, we might have been able to get away with letting one slide.”

Should I upgrade my mask?

You should be wearing a high-quality mask when you run errands, go shopping or find yourself in a situation where you’re spending time indoors with people who don’t live with you, Dr. Marr said. “I am now wearing my best mask when I go to the grocery store,” she said. “The last thing I want to do is get Covid-19 in the month before I get vaccinated.”

Dr. Marr’s lab recently tested 11 mask materials and found that the right cloth mask, properly fitted, does a good job of filtering viral particles of the size most likely to cause infection. The best mask has three layers — two cloth layers with a filter sandwiched in between. Masks should be fitted around the bridge of the nose and made of flexible material to reduce gaps. Head ties create a better fit than ear loops.


Covid-19 Vaccines ›


Answers to Your Vaccine Questions

While the exact order of vaccine recipients may vary by state, most will likely put medical workers and residents of long-term care facilities first. If you want to understand how this decision is getting made, this article will help.

Life will return to normal only when society as a whole gains enough protection against the coronavirus. Once countries authorize a vaccine, they’ll only be able to vaccinate a few percent of their citizens at most in the first couple months. The unvaccinated majority will still remain vulnerable to getting infected. A growing number of coronavirus vaccines are showing robust protection against becoming sick. But it’s also possible for people to spread the virus without even knowing they’re infected because they experience only mild symptoms or none at all. Scientists don’t yet know if the vaccines also block the transmission of the coronavirus. So for the time being, even vaccinated people will need to wear masks, avoid indoor crowds, and so on. Once enough people get vaccinated, it will become very difficult for the coronavirus to find vulnerable people to infect. Depending on how quickly we as a society achieve that goal, life might start approaching something like normal by the fall 2021.

Yes, but not forever. The two vaccines that will potentially get authorized this month clearly protect people from getting sick with Covid-19. But the clinical trials that delivered these results were not designed to determine whether vaccinated people could still spread the coronavirus without developing symptoms. That remains a possibility. We know that people who are naturally infected by the coronavirus can spread it while they’re not experiencing any cough or other symptoms. Researchers will be intensely studying this question as the vaccines roll out. In the meantime, even vaccinated people will need to think of themselves as possible spreaders.

The Pfizer and BioNTech vaccine is delivered as a shot in the arm, like other typical vaccines. The injection won’t be any different from ones you’ve gotten before. Tens of thousands of people have already received the vaccines, and none of them have reported any serious health problems. But some of them have felt short-lived discomfort, including aches and flu-like symptoms that typically last a day. It’s possible that people may need to plan to take a day off work or school after the second shot. While these experiences aren’t pleasant, they are a good sign: they are the result of your own immune system encountering the vaccine and mounting a potent response that will provide long-lasting immunity.

No. The vaccines from Moderna and Pfizer use a genetic molecule to prime the immune system. That molecule, known as mRNA, is eventually destroyed by the body. The mRNA is packaged in an oily bubble that can fuse to a cell, allowing the molecule to slip in. The cell uses the mRNA to make proteins from the coronavirus, which can stimulate the immune system. At any moment, each of our cells may contain hundreds of thousands of mRNA molecules, which they produce in order to make proteins of their own. Once those proteins are made, our cells then shred the mRNA with special enzymes. The mRNA molecules our cells make can only survive a matter of minutes. The mRNA in vaccines is engineered to withstand the cell’s enzymes a bit longer, so that the cells can make extra virus proteins and prompt a stronger immune response. But the mRNA can only last for a few days at most before they are destroyed.

If you don’t want to buy a new mask, a simple solution is to wear an additional mask when you find yourself in closer proximity to strangers. I wear a single mask when I walk my dog or exercise outdoors. But if I’m going to a store, taking a taxi or getting in the subway, I double mask by using a disposable surgical mask and covering it with my cloth mask.

Do I need an N95 medical mask?

While medical workers who come into close contact with sick patients rely on the gold-standard N95 masks, you don’t need that level of protection if you’re avoiding group gatherings, limiting shopping trips and keeping your distance from others.

“N95s are hard to get,” said Dr. Jha. “I don’t think people should think that’s what they need. Certainly there are a lot of masks out in the marketplace that are pretty good.”

If you’re working in an office or grocery store, or find yourself in a situation where you want added mask protection, you can get an alternative to the N95. Dr. Jha suggested using a KF94 mask, a type of mask made in South Korea that can be purchased easily online. It resembles an N95, with some differences. It’s made of a similar nonwoven material that blocks 94 percent of the hardest-to-trap viral particles. But the KF94 has ear loops, instead of elastic head bands, so it won’t fit as snugly as an N95.

The KF94 is also disposable — you can buy a pack of 20 for about $40 on Amazon. While you can let a KF94 mask air dry and reuse it a few times, it can’t be laundered and won’t last as long as a cloth mask. One solution is to save your KF94 mask for higher risk situations — like riding a subway, spending time in a store or going to a doctor’s appointment. Use your cloth mask for outdoor errands, exercise or walking the dog.

Are there additional ways to reduce my risk?

Getting the vaccine is the ultimate way to reduce risk. But until then, take a look at your activities and try reducing the time and number of exposures to other people.

For instance, if you now go to the store two or three times a week, cut back to just once a week. If you’ve been spending 30 to 45 minutes in the grocery store, cut your time down to 15 or 20 minutes. If the store is crowded, come back later. If you’re waiting in line, be mindful of staying at least six feet apart from the people ahead of you and behind you. Try delivery or curbside pickup, if that’s an option for you.

If you’ve been spending time indoors with other people who aren’t from your household, consider skipping those events until you and your friends get vaccinated. If you must spend time with others, wear your best mask, make sure the space is well ventilated (open windows and doors) and keep the visit as short as possible. It’s still safest to take your social plans outdoors. And if you are thinking about air travel, it’s a good idea to reschedule given the high number of cases around the country and the emergence of the more contagious variant.

“The new variants are making me think twice about my plan to teach in-person, which would have been with masks and with good ventilation anyway,” Dr. Marr said. “They’re making me think twice about getting on an airplane.”

Will the current Covid vaccines work against the new variants?

Experts are cautiously optimistic that the current generation of vaccines will be mostly effective against the emerging coronavirus variants. Earlier this month, Pfizer and BioNTech announced that their Covid vaccine works against one of the key mutations present in some of the variants. That’s good news, but the variants have other potentially risky mutations that haven’t been studied yet.

Some data also suggest that variants with certain mutations may be more resistant to the vaccines, but far more study is needed and those variants haven’t yet been detected in the United States. While the data are concerning, experts said the current vaccines generate extremely high levels of antibodies, and they are likely to at least prevent serious illness in people who are immunized and get infected.

“The reason why I’m cautiously optimistic is that from what we know about how vaccines work, it’s not just one antibody that provides all the protection,” said Dr. Adam Lauring, associate professor of infectious disease at the University of Michigan. “When you get vaccinated you generate antibodies all over the spike protein. That makes it less likely that one mutation here or there is going to leave you completely unprotected. That’s what gives me reason for optimism that this is going to be OK in terms of the vaccine, but there’s more work to be done.”

If I catch Covid-19, will I know if I have the new variant?

Probably not. If you test positive for Covid-19, the standard PCR test can’t definitively determine if you have the variant or the original strain. While some PCR test results can signal if a person is likely to be infected with a variant, that information probably won’t be shared with patients. The only way to know for sure which variant is circulating is to use gene sequencing technology, but that technology is not used to alert individuals of their status. While some public health and university laboratories are using genomic surveillance to track the prevalence of variants in a community, the United States doesn’t yet have a large-scale, nationwide system for checking coronavirus genomes for new mutations.

Treatment for Covid-19 is the same whether you have the original strain or the variant. You can read more about what to do if you get infected here.

Are children more at risk from the new variant?

Children appear to get infected with the variant at about the same rate as the original strain. A large study by health officials in Britain found that young children are only about half as likely as adults to transmit the variant to others. While that’s good news, the highly contagious nature of the variant means more children will get the virus, even if they are still proportionately less contagious and less prone to getting infected than adults. You can learn more here.

If I’ve already had Covid-19, am I likely to have the same level of immunity to the new strain?

Most experts agree that once you’ve had Covid-19, your body has some level of natural immunity to help fight off a second infection — although it’s not known how long the protection lasts. The variants circulating in Brazil and South Africa appear to have mutations that allow the virus to evade natural antibodies and reinfect someone who has already had the virus. The concern is based on lab tests using antibodies of people with a previous infection, so whether that translates to more reinfections in the real world isn’t known. The effect of the vaccine against these variants isn’t known yet either. While all of this sounds frightening, scientists are hopeful that even if the vaccines don’t fully protect against new variations of the virus, the antibodies generated by the vaccine still will protect people from more serious illness.

How to (Literally) Drive the Coronavirus Away

How to (Literally) Drive the Coronavirus Away

What’s the transmission risk inside a car? An airflow study offers some insight for passengers and drivers alike.

Although cars don’t carry enough people to host a traditional superspreader event, they are small, sealed spaces that can still carry the risk of Covid-19 transmission.
Although cars don’t carry enough people to host a traditional superspreader event, they are small, sealed spaces that can still carry the risk of Covid-19 transmission.Credit…Matt Rourke/Associated Press

  • Jan. 16, 2021, 5:00 a.m. ET

Over the past year, as the health authorities have tried to curb the Covid-19 pandemic, researchers have trained their scientific attention on a variety of potentially risky environments: places where large groups of people gather and the novel coronavirus has ample opportunity to spread. They have swabbed surfaces on cruise ships, tracked case numbers in gyms, sampled ventilation units in hospitals, mapped seating arrangements in restaurants and modeled boarding procedures in airplanes.

They have paid less attention to another everyday environment: the car. A typical car, of course, does not carry nearly enough people to host a traditional super-spreader event. But cars come with risks of their own; they are small, tightly sealed spaces that make social distancing impossible and trap the tiny, airborne particles, or aerosols, that can transmit the coronavirus.

“Even if you’re wearing a face covering, you still get tiny aerosols that are released every time you breathe,” said Varghese Mathai, a physicist at the University of Massachusetts, Amherst. “And if it’s a confined cabin, then you keep releasing these tiny particles, and they naturally would build up over time.”

In a new study, Dr. Mathai and three colleagues at Brown University — Asimanshu Das, Jeffrey Bailey and Kenneth Breuer — used computer simulations to map how virus-laden airborne particles might flow through the inside of a car. Their results, published in early January in Science Advances, suggest that opening certain windows can create air currents that could help keep both riders and drivers safe from infectious diseases like Covid-19.

To conduct the study, the research team employed what are known as computational fluid dynamic simulations. Engineers commonly use these kinds of computer simulations, which model how gases or liquids move, to create racecars with lower drag, for instance, or airplanes with better lift.

The team simulated a car loosely based on a Toyota Prius driving at 50 miles per hour, with two occupants: a driver in the front left seat and a single passenger in the back right, a seating arrangement that is common in taxis and ride shares and that maximizes social distancing. In their initial analysis, the researchers found that the way the air flows around the outside of the moving car creates a pressure gradient inside the car, with the air pressure in the front slightly lower than the air pressure in the back. As a result, air circulating inside the cabin tends to flow from the back of the car to the front.

A diagram showing air circulation in a car with the front right and rear left windows open. A pressure gradient causes the air to generally flow from back to front in the car.
A diagram showing air circulation in a car with the front right and rear left windows open. A pressure gradient causes the air to generally flow from back to front in the car.Credit…Mathai et al., Science Advances 2021

Next, they modeled the interior air flow — and the movement of simulated aerosols — when different combinations of windows were open or closed. (The air-conditioning was on in all scenarios.) Unsurprisingly, they found that the ventilation rate was lowest when all four windows were closed. In this scenario, roughly 8 to 10 percent of aerosols exhaled by one of the car’s occupants could reach the other person, the simulation suggested. When all the windows were completely open, on the other hand, ventilation rates soared, and the influx of fresh air flushed many of the airborne particles out of the car; just 0.2 to 2 percent of the simulated aerosols traveled between driver and passenger.

The results jibe with public health guidelines that recommend opening windows to reduce the spread of the novel coronavirus in enclosed spaces. “It’s essentially bringing the outdoors inside, and we know that the risk outdoors is very low,” said Joseph Allen, a ventilation expert at the Harvard T.H. Chan School of Public Health. In an op-ed last year, he highlighted the danger that cars could pose for coronavirus transmission, and the potential benefits of opening the windows. “When you have that much turnover of air, the residence time, or how much time the aerosols stay inside the cabin, is very short,” Dr. Allen said

Because it’s not always practical to have all the windows wide open, especially in the depths of winter, Dr. Mathai and his colleagues also modeled several other options. They found that while the most intuitive-seeming solution — having the driver and the passenger each roll down their own windows — was better than keeping all the windows closed, an even better strategy was to open the windows that are opposite each occupant. That configuration allows fresh air to flow in through the back left window and out through the front right window and helps create a barrier between the driver and the passenger.

“It’s like an air curtain,” Dr. Mathai said. “It flushes out all the air that’s released by the passenger, and it also creates a strong wind region in between the driver and the passenger.”

Richard Corsi, an air quality expert at Portland State University, praised the new study. “It’s pretty sophisticated, what they did,” he said, although he cautioned that changing the number of passengers in the car or the driving speed could affect the results.

Dr. Corsi, a co-author of the op-ed with Dr. Allen last year, has since developed his own model of the inhalation of coronavirus aerosols in various situations. His results, which have not yet been published, suggest that a 20-minute car ride with someone who is emitting infectious coronavirus particles can be much riskier than sharing a classroom or a restaurant with that person for more than an hour.

“The focus has been on superspreader events” because they involve a lot of people, he said. “But I think what sometimes people miss is that superspreader events are started by somebody who’s infected who comes to that event, and we don’t speak often enough about where that person got infected.”

In a follow-up study, which has not yet been published, Dr. Mathai found that opening the windows halfway seemed to provide about the same benefit as opening them fully, while cracking them just one-quarter of the way open was less effective.

Dr. Mathai said that the general findings would most likely hold for many four-door, five-seat cars, not just the Prius. “For minivans and pickups, I would still say that opening all windows or opening at least two windows can be beneficial,” he said. “Beyond that, I would be extrapolating too much.”

Ride-sharing companies should be encouraging this research, Dr. Mathai said. He sent a copy of his study to Uber and Lyft, he said, but has not received a response.

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A Riot Amid a Pandemic: Did the Virus, Too, Storm the Capitol?

A Riot Amid a Pandemic: Did the Virus, Too, Storm the Capitol?

Some scientists fear that the mayhem on Capitol Hill may have led to a so-called super-spreading event.

The rally on the National Mall before a mob entered the Capitol on Wednesday.
The rally on the National Mall before a mob entered the Capitol on Wednesday.Credit…Pete Marovich for The New York Times
Apoorva Mandavilli

  • Jan. 7, 2021, 3:29 p.m. ET

The mob that stormed the Capitol yesterday did not just threaten the heart of American democracy. To scientists who watched dismayed as the scenes unfolded on television, the throngs of unmasked intruders who wandered through hallways and into private offices may also have transformed the riot into a super-spreader event.

The coronavirus thrives indoors, particularly in crowded spaces, lingering in the air in tiny particles called aerosols. If even a few extremists were infected — likely, given the current rates of spread and the crowd size — then the virus would have had the ideal opportunity to find new victims, experts said.

“It has all the elements of what we warn people about,” said Anne Rimoin, an epidemiologist at the University of California, Los Angeles. “People yelling and screaming, chanting, exerting themselves — all of those things provide opportunity for the virus to spread, and this virus takes those opportunities.”

President Trump has downplayed the pandemic almost since its beginning, and many of his supporters who entered the Capitol yesterday did not appear to be wearing masks or making any effort at social distancing. Under similar conditions, gatherings held in such close quarters have led to fast-spreading clusters of infection.

But transmission of the virus has always been difficult to track. There is little effective contact tracing in the United States, and many in the crowd at the Capitol arrived from communities far from Washington.

The Black Lives Matter protests in the summer raised similar concerns. But most were held outdoors, and greater numbers of participants seemed to be masked. Research afterward suggested these were not super-spreading events.

Attendees of the rally preceding the rush to the Capitol on Wednesday also stood outdoors close together for hours, but “I’m less worried about what was happening outdoors,” Dr. Rimoin said. “The risk increases exponentially indoors.”

Rioters in the National Statuary Hall in the Capitol on Wednesday.
Rioters in the National Statuary Hall in the Capitol on Wednesday.Credit…Anna Moneymaker for The New York Times

Hundreds of rioters shouting in crowded rooms and hallways for extended periods of time can infect dozens of people at once, she and other experts said.

Three distinct groups — Capitol Police, rioters and members of Congress — “were spending time indoors, without social distancing, for long periods of time,” said Dr. Joshua Barocas, an infectious diseases physician at Boston University. The melee likely was a super-spreader event, he added, “especially given the backdrop of the highly transmissible variants that are circulating.”

Dr. Barocas was referring to a highly contagious new variant of the coronavirus, first identified in Britain. It has been spotted in several U.S. states but may well have spread everywhere in the country, making events like the Capitol riot even more risky, he said.

The idea that members of Congress may have been exposed, amid an already difficult transfer of power, particularly disturbed some scientists. “I am worried not only that it could it could lead to super spreading, but also super spreading to people who are elected officials,” said Dr. Tom Ingelsby, director of the Center for Health Security at Johns Hopkins University.

And infected members of Congress and law enforcement could have spread the virus to one another as they sheltered from the violence, he noted.

Rep. Jake LaTurner, Republican of Kansas, announced on Twitter early Thursday morning that he had tested positive for the virus. Mr. LaTurner was cloistered in the chamber with other members of Congress for much of the day.

At least a dozen of the 400 or so lawmakers and staff who were huddling in one committee room refused to wear masks even after being offered one, or wore them improperly below their chins, said Representative Susan Wild, Democrat of Pennsylvania.

They gathered in a committee room that quickly became crowded, making social distancing impossible, she said. Some of the lawmakers were unmasked, and several were shouting: “Tensions were high, and people were yelling at each other.”

“I just started getting really kind of angry, thinking about the holidays just passed, and how so many people did not spend time with their immediate families for fear of spreading,” she added, referring to her unmasked colleagues.

Representative Debbie Dingell, Democrat of Michigan, said the environment made her so nervous she sat on the floor at one point, hoping to duck whatever virus might be floating about. She has asked experts whether the lawmakers present should now quarantine, she said. She was wearing two masks, as she often does.

“I get that they think they have their individual freedoms,” she said of Republican lawmakers who eschewed masks. “It’s a rule for a reason. It’s to protect the common good.”

Electoral College votes were returned to a joint session of Congress late Wednesday.Credit…Erin Schaff/The New York Times

The risk for members of Congress will depend greatly on ventilation in the room where they sheltered, said Joseph Allen, an expert on buildings quality at the Harvard T.H. Chan School of Public Health in Boston.

“If there is a well-designed secure facility, then it would have great ventilation and filtration,” Dr. Allen said. “If it’s a place where they were just hunkered down wherever they could go that was safe, and it was not a place that was designed like that, then we don’t really know.”

It’s natural in a heart-pounding crisis to disregard risks that seem intangible or theoretical, he and other scientists noted.

“You cannot keep distance if you’re trying to leave a very intense and dangerous situation,” said Seema Lakdawala, an expert in respiratory virus transmission at the University of Pittsburgh. “You’re weighing the risk of your life over the risk of getting a virus at that moment.”

Members of Congress returned to continue the electoral count after the rioters were cleared from the Capitol. Some legislators took off their masks before giving a speech, Dr. Barocas noted, at precisely the time they needed to wear them. Talking at a high volume can expel vast quantities of aerosols, propelling them through an enclosed space.

Scientists have documented infectious aerosols suspended in air nearly 20 feet from an infected person. And a recent study from South Korea found that two people had become infected after spending just five minutes in a restaurant, 15 feet away from an infected patron.

Many Americans breathed sighs of relief as rioters departed the Capitol. Some experts feared that rioters heading back home could set off new chains of infection, perhaps impossible to track.

“We might get an inkling into how bad it might be because of the federal employees,” Dr. Barocas said. But “I don’t think that we’re going to know the extent of this super-spreader event.”

Even as the mob stormed the Capitol on Wednesday, the pandemic marked a grim milestone: The virus claimed nearly 4,000 lives, the highest daily toll thus far. The numbers are expected to keep rising.

The president has “created a culture in which people think it’s a hoax, and these basic control measures are being flouted repeatedly everywhere,” Dr. Allen said.