Tagged Influenza

Emerging Coronavirus Variants May Pose Challenges to Vaccines

Emerging Coronavirus Variants May Pose Challenges to Vaccines

Laboratory studies of mutations circulating in South Africa suggest they may dodge some of the body’s immune responses.

Health workers tended to a Covid-19 patient at Greenacres Hospital in Port Elizabeth, South Africa, in November.
Health workers tended to a Covid-19 patient at Greenacres Hospital in Port Elizabeth, South Africa, in November.Credit…Samantha Reinders for The New York Times
Apoorva Mandavilli

  • Jan. 20, 2021, 6:37 p.m. ET

The steady drumbeat of reports about new variants of the coronavirus — first in Britain, then in South Africa, Brazil and the United States — have brought a new worry: Will vaccines protect against these altered versions of the virus?

The answer so far is yes, several experts said in interviews. But two small new studies, posted online Tuesday night, suggest that some variants may pose unexpected challenges to the immune system, even in those who have been vaccinated — a development that most scientists had not anticipated seeing for months, even years.

The findings result from laboratory experiments with blood samples from groups of patients, not observations of the virus spreading in the real world. The studies have not yet been peer-reviewed.

But experts who reviewed the papers agreed that the findings raised two disturbing possibilities. People who had survived mild infections with the coronavirus may still be vulnerable to infection with a new variant; and more worryingly, the vaccines may be less effective against the variants.

Existing vaccines will still prevent serious illness, and people should continue getting them, said Dr. Michel Nussenzweig, an immunologist at Rockefeller University in New York, who led one of the studies: “If your goal is to keep people out of the hospital, then this is going to work just fine.”

But the vaccines may not prevent people from becoming mildly or asymptomatically infected with the variants, he said. “They may not even know that they were infected,” Dr. Nussenzweig added. If the infected can still transmit the virus to others who are not immunized, it will continue to claim lives.

The vaccines work by stimulating the body to produce antibodies against the coronavirus. Scientists had expected that over time, the virus may gain mutations that allow it to evade these antibodies — so-called escape mutations. Some studies had even predicted which mutations would be most advantageous to the virus.

But scientists had hoped that the new vaccines would remain effective for years, on the theory that the coronavirus would be slow to develop new defenses against them. Now some researchers fear the unchecked spread has given the virus nearly unfettered opportunities to reinvent itself, and may have hastened the appearance of escape mutations.

The studies published on Tuesday night show that the variant identified in South Africa is less susceptible to the antibodies created by natural infection and by vaccines made by Pfizer-BioNTech and Moderna.

Vaccinations of nurses, doctors and health professionals in São Paulo, Brazil, this week.
Vaccinations of nurses, doctors and health professionals in São Paulo, Brazil, this week.Credit…Victor Moriyama for The New York Times

Neither the South African variant nor a similar mutant virus in Brazil has yet been detected in the United States. (The more contagious variant that has blazed through Britain does not contain these mutations and seems to be susceptible to vaccines.)

Fears that the vaccines would be powerless against new variants intensified at a scientific conference held online on Saturday, when South African scientists reported that in laboratory tests, serum samples from 21 of a group of 44 Covid-19 survivors did not destroy the variant circulating in that country.

The samples that were successful against the variant were taken from patients who had been hospitalized. These patients had higher blood levels of so-called neutralizing antibodies — the subset of antibodies needed to disarm the virus and prevent infection — than those who were only mildly ill.

The results “strongly, strongly suggest that several mutations that we see in the South Africa variant are going to have a significant effect on the sensitivity of that virus to neutralization,” said Penny Moore, a virologist at the National Institute for Communicable Diseases in South Africa who led the study.

The second study brought better tidings, at least about vaccines.

In that study, Dr. Nussenzweig and his colleagues tested samples from 14 people who had received the Moderna vaccine and six people who had received the Pfizer-BioNTech vaccine.


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.

The researchers saw a slight decrease in antibody activity directed against engineered viruses with three of the key mutations in the variant identified in South Africa. That result was significant “because it’s seen in just about every individual tested,” Dr. Nussenzweig said. Still, it “is not something that we should be horribly freaked out about.”

In most people, infection with the coronavirus leads to a strong immune response; the vaccines seem to induce an even more powerful response. Two doses of the vaccines from Pfizer and Moderna, at least, produce neutralizing antibodies at levels that are higher than those acquired through natural infection.

Even if antibody effectiveness were reduced tenfold, the vaccines would still be quite effective against the virus, said Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle.

In Liverpool, England, people lined up to receive a coronavirus test at a recreational tennis center last year.Credit…Mary Turner for The New York Times

And while neutralizing antibodies are essential for preventing infection, the vaccines — and natural infection — also lead to production of thousands of other types of antibodies, not to mention various immune cells that retain a memory of the virus and can be roused to action when the body encounters it again.

Even when confronted with variants, those other components of the immune system may be enough to prevent serious illness, said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York. In clinical trials, the vaccines protected people from illness after just one dose, when the levels of neutralizing antibodies were low or undetectable, he noted.

Vaccine trials being conducted in South Africa by Novavax and Johnson & Johnson will provide more real-world data on how the vaccines perform against the new variant there. Those results are expected within the next few weeks.

All viruses mutate, and it’s no surprise that some of those mutations sidestep the body’s immune defenses, experts said. Each new host affords a virus fresh opportunities to amass and test mutations by slightly scrambling the sequence of RNA letters in its genetic code.

“The beauty, the elegance, the evolution and the magnificence of a virus is that every single time it infects a person, it’s exploring that sequence space,” said Paul Duprex, director of the Center for Vaccine Research at the University of Pittsburgh.

Some mutations don’t improve on the original, and fade away. Others add to the pathogen’s power, by making it more contagious — like the variant first identified in Britain — more fit, or less susceptible to immunity.

The mutations in the variant circulating in South Africa, called B.1.351, have independently emerged more than once, and all together, suggesting that they work in concert to benefit the virus.

A field hospital for treating Covid-19 patients outside Port Elizabeth, South Africa, in November. Credit…Samantha Reinders for The New York Times

The key mutation, called E484K, and two of its companions alter the shape of a part of the virus that is crucial for immune recognition, making it difficult for antibodies to attach themselves to the virus. The trio popped up in several lab studies that tried to predict which mutations would be advantageous to the virus.

“I think we need to monitor mutations closely and look out for things like that that could be becoming dominant in certain parts of the world,” said Akiko Iwasaki, an immunologist at Yale University.

Britain detected the more contagious variant circulating there because it sequences more virus samples than any other nation. The United States lags far behind: It has sequenced about 71,000 samples so far, a tiny proportion of the millions infected in the country. But the Centers for Disease Control and Prevention plans to work with state and local public health labs to sequence as many as 6,000 samples per week, agency scientists said Friday.

It will be important to limit travel — and the import of variants — from other countries until a majority of the population is immunized, said John Moore, a virologist at Weill Cornell Medicine in New York.

“Even if they are already here, the more often they are reintroduced, the more likely there could be a super-spreader event,” Dr. Moore said. (President Joseph R. Biden Jr. plans to sustain existing travel restrictions on anyone who has recently traveled to Europe and Brazil.)

The mRNA technology on which the Pfizer and Moderna vaccines rely can be altered in a matter of weeks, and far more easily than the process used to produce flu vaccines. But it would be wise to prepare for this eventuality now and think through not just the technical aspects of updating the vaccines, but the testing, approval and rollout of those vaccines, experts said.

Still, the best path forward is to prevent the emergence of new mutations and variants altogether, they said.

“Imagine having to do catch-up like this all the time — it’s not something desirable,” Dr. Iwasaki said. “If we can just stop the spread as soon as possible, while the vaccine is very effective, that’s the best way.”

Don’t Let the Pandemic Stop Your Shots

the new old age

Don’t Let the Pandemic Stop Your Shots

Even as older adults await the coronavirus vaccine, many are skipping the standard ones. That’s not wise, health experts say.

Credit…Chris Lyons

  • Dec. 28, 2020, 12:12 p.m. ET

Peggy Stein, 68, a retired teacher in Berkeley, Calif., skipped a flu shot this year. Her reasoning: “How could I get the flu if I’m being so incredibly careful because of Covid?”

Karen Freeman, 74, keeps meaning to be vaccinated against shingles, but hasn’t done so. A retired college administrator in St. Louis, she quipped that “denial has worked well for me these many years.”

Sheila Blais, who lives on a farm in West Hebron, N.Y., has never received any adult vaccine. She also has never contracted the flu. “I’m such an introvert I barely leave the farm, so where’s my exposure?” said Ms. Blais, 66, a fiber artist. “If it’s not broke, don’t fix it.”

While older adults await vaccination against Covid-19, public health officials also worry about their forgoing, forgetting, fearing or simply not knowing about those other vaccines — the ones recommended for adults as we age and our immune systems weaken.

“There’s a lot of room for improvement,” said Dr. Ram Koppaka, associate director for adult immunization at the Centers for Disease Control and Prevention.

Every year, campaigns urge older adults to protect themselves against preventable infectious diseases. After all, influenza alone has killed 12,000 to 61,000 Americans annually over the past decade, most of them 65 or older, and has sent 140,000 to 810,000 people a year to hospitals.

The coronavirus pandemic has introduced another imperative. Those hospitals are filling fast with Covid-19 patients; in many places they are already swamped, their staffs overworked and exhausted.

“Knowing how stressed the health care system is, prevention is key,” said Dr. Nadine Rouphael, a vaccine researcher and infectious disease specialist at Emory University. “When we have record numbers of deaths, why would you go to a hospital for a vaccine-preventable illness?”

Yet the nation has long done a better job of vaccinating its children than its elders. The most recent statistics, from 2017, show that about one-third of adults over 65 had not received a flu shot within the past year. About 30 percent had not received the pneumococcus vaccine.

The proportion receiving the shingles vaccine, a fairly recent addition to the list, has inched up, but by 2018 only 34.5 percent of people over 60 had been vaccinated.

Moreover, Dr. Koppaka pointed out: “When you look deeper, there are longstanding, deep, significant differences in the proportion of Black and Hispanic adults getting vaccines compared to their white counterparts. It’s really unacceptable.”

Close to 40 percent of non-Hispanic whites had been vaccinated against shingles, for instance, compared with fewer than 20 percent of Blacks and Hispanics.

One might expect a group who can recall polio fears and outbreaks of whooping cough to be less hesitant to get vaccinated than younger cohorts. “You’ll probably have a different concept of vaccination from someone who never experienced what a serious viral illness can do,” Dr. Koppaka said.

When it comes to the Covid-19 vaccine, for instance, only 15 percent of those over 65 say they would definitely or probably not get it, compared with 36 percent of those 30 to 49, a Kaiser Family Foundation tracking poll showed earlier this month. (Ms. Stein, Ms. Blais and Ms. Freeman all said they would happily accept the Covid vaccine.)

But for other diseases, vaccination rates lag. Given that older people are more vulnerable to severe illness from them, why the gaps in coverage?

Internists and other doctors for adults don’t promote vaccines nearly as effectively as pediatricians do, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University. Older patients, who often see a variety of doctors, may also have trouble keeping track of when they got which shot.

Experts fear that vaccination rates may have fallen further during the pandemic, as they have among children, if older people wary of going to doctors’ offices or pharmacies skipped shots.

Financial and bureaucratic obstacles also thwart vaccination efforts. Medicare Part B covers three vaccines completely: influenza, pneumococcus and, when indicated, hepatitis B.

The Tdap and shingles vaccines, however, are covered under Part D, which can complicate reimbursement for doctors; the vaccines are easier to obtain in pharmacies. Not all Medicare recipients buy Part D, and for those who do, coverage varies by plan and can include deductibles and co-pays.

Still, older adults can gain access to most recommended vaccines for no or low cost, through doctors’ offices, pharmacies, supermarkets and local health departments. For everyone’s benefit, they should.

Here’s what the C.D.C. recommends:

Influenza An annual shot in the fall — and it’s still not too late, because flu season peaks from late January into February. Depending on which strain is circulating, the vaccine (ask for the stronger versions for seniors) prevents 40 to 50 percent of cases; it also reduces illness severity for those infected.

Thus far this year, flu activity has remained extraordinarily low, perhaps because of social distancing and masks or because closed schools kept children from spreading it. Manufacturers shipped a record number of doses, so maybe more people got vaccinated. In any case, fears of a flu/Covid “twindemic” have not yet been realized.

Nevertheless, infectious disease experts urge older adults (and everyone over six months old) to get flu shots now. “Flu is fickle,” Dr. Schaffner said. “It could take off like a rocket in January.”

Tetanus, diphtheria, pertussis. A booster of TD vaccine every 10 years, to prevent tetanus and diphtheria. If you’ve never had the Tdap vaccine — which adds prevention against pertussis — that’s the one you want. Although pertussis, better known as whooping cough, occasionally shows up in adults, newborns are particularly at risk. Pregnant women will ask expectant grandparents to get a Tdap shot. Because it is covered under Part D, a pharmacy is the best bet.

Pneumococcus. “It’s a pneumonia vaccine, but it also prevents the most serious consequences of pneumonia, including meningitis and bloodstream infections,” Dr. Koppaka said.

People over 65 should get the polysaccharide formula — brand name Pneumovax — but there are certain circumstances, such as immune-compromising conditions, to discuss with a health care provider.

Those over 65 may choose, again in consultation with a provider, to also get the conjugate pneumococcal vaccine (brand name Prevnar), which provides some additional protection. If so, C.D.C. guidelines specify which vaccine to take when.

Shingles. Social distancing won’t ward off this disease; anyone who had chickenpox, which is just about every senior, still carries the virus.

“If you live to be 80, you stand a 35 to 50 percent chance of having an episode,” Dr. Schaffner said. “And the older you are when you get it, the more apt you are to get the most serious complication” — lingering nerve pain called post-herpetic neuralgia.

The C.D.C. recommends Shingrix, the highly effective shingles vaccine the F.D.A. approved in 2017, for everyone over 50. The previous shingles vaccine has been discontinued. Get Shingrix even if you had the earlier vaccine, Zostavax, and even if you’ve had shingles — it can recur.

The two required shots, given two to six months apart, can total $300 out of pocket. But Medicare Part D beneficiaries will pay an average of $50 for the pair, said a spokesman for the manufacturer GlaxoSmithKline, and people with private insurance even less.

Hepatitis A and hepatitis B. These aren’t age-related; the vaccines are recommended for people with certain health conditions, including chronic liver disease and H.I.V. infection, or for travelers to countries where the diseases are widespread.

The hepatitis B vaccine is also recommended, at a provider’s discretion, for diabetics over 60 who haven’t been previously vaccinated. Talk to a health care professional about your risks.

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Covid Vaccine During Pregnancy? Even Doctors Struggle With This Question

Doctors

I’m a Pregnant Doctor. Should I Get the Covid Vaccine?

A doctor struggles with the lack of data surrounding the Covid-19 vaccine and pregnancy.

Credit…Nam Y. Huh/Associated Press

  • Dec. 22, 2020, 5:00 a.m. ET

The morning after the Food and Drug Administration approved the emergency use authorization of the first coronavirus vaccine, I awoke to a message from my hospital asking me to sign up for an appointment to get vaccinated.

It brought tears to my eyes. As a primary care doctor, I haven’t exactly been on the front lines of the Covid-19 fight, but it’s upended my life and the lives of my patients. With the vaccine’s approval — and now a second one — we finally have an end in sight. Within hours, my colleagues were all texting each other, abuzz with the excitement of scheduling their vaccine appointments.

But I quickly learned I have an impossible choice ahead of me.

I am pregnant, and all of the clinical trials on Covid-19 vaccines excluded pregnant people. This is no surprise: pregnant people are frequently left out of clinical research because of the complexity of pregnancy, including concerns about potential harm to the fetus. That leaves us with little data to help us make decisions about medications and vaccines.

Instead we’re on our own, winging it during an already vulnerable time. And as I care for a ballooning number of coronavirus-positive patients each day, my decision about the vaccine seems more urgent than ever.

The news of my pregnancy was a joyful moment for my family in a difficult year, but Covid-19 has been a terrifying backdrop. I practice in Camden, N.J., and our community has been hard-hit. Infections are soaring above the springtime peak. My inbox contains positive case after positive case.

My patients are the most essential of essential workers — home health aides, warehouse workers, janitors — still, even after all we’ve learned this year, with little job security, minimal paid sick leave and inadequate personal protective equipment. And as my patients get exposed to the virus, so do I.

The data on coronavirus infection during pregnancy are not reassuring. Pregnant people who get the virus seem to have a higher risk for severe symptoms and complications, and there also may be a small increased risk of preterm birth. Each day I walk into my clinic, I ask myself, “Will this be the day I get it?”

The early news about the efficacy of the vaccines was thrilling. But there has been little data on how the vaccine affects pregnant people. No pregnant patients were enrolled in the early trials, although some people got pregnant during the course of the study. Researchers are monitoring them to see how they do.

According to Ruth Faden, a Johns Hopkins bioethicist who studies vaccine policy, the reluctance to include pregnant research subjects in clinical trials has a long history.

“There’s an inertia that’s set in,” she told me. Studying pregnant people requires extra effort in safe study design and recruitment efforts, so rather than do the hard work, she says, pregnant women are often just excluded altogether.

“It’s an ethically complex situation,” she added. “Pregnancy is like nothing else. Anything you do to a pregnant woman also has a chance of affecting the developing offspring.”

Researchers estimate we have adequate data on the risk of birth defects in less than 10 percent of medications approved by the Food and Drug Administration since 1980. That means any time a pregnant person thinks about using a medication or vaccine, she might feel like she’s making a decision at random, without any rigorous information to guide her.

That’s certainly how I feel right now. My medical training taught me to respect my patients’ autonomy; I see my job as guiding them through confusing medical information and helping them make decisions, not making decisions for them. Patient autonomy is a primary value in medicine.

I was glad to see that the F.D.A. left the choice of whether or not to get the Covid-19 vaccine up to pregnant women, rather than excluding us from eligibility altogether. For a pregnant nursing home aide, or a pregnant intensive care unit nurse, the risk of getting Covid-19 might be greater than the risk of any potential vaccine side effects.

This isn’t a theoretical exercise for hundreds of thousands of health care workers. Women make up an estimated 76 percent of the health care work force, many of us of childbearing age. I have text message chains with several pregnant and breastfeeding physician friends, all of us trying to sort through the limited information we have.

But without any data to guide me, my autonomy to make the decision doesn’t feel as meaningful. The American College of Obstetricians and Gynecologists offered this wildly unsatisfying recommendation: “Covid-19 vaccines should not be withheld from pregnant individuals who meet criteria for vaccination.” The Centers for Disease Control and Prevention issued similarly noncommittal guidance: “Health care personnel who are pregnant may choose to be vaccinated.” Both are a far cry from the two organizations’ enthusiastic support for the flu vaccine in pregnancy, for example.

So it’s up to me and my nurse midwife, both of us smart clinicians, but not vaccine experts. I asked her what she thought, and she told me, “Honestly, I have no idea.”

I try to weigh the costs and benefits: I care for positive patients, but it’s not as if I’m an I.C.U. doctor. Many vaccines are safe in pregnancy — I gladly got my flu shot early on — but other vaccines aren’t. How can I weigh the costs and benefits if I don’t know what the costs are?

The two vaccines that have now been approved use a novel messenger RNA technology that has not been studied in pregnancy. It’s possible the mRNA and the bubble it travels in, made of lipid nanoparticles, could cross the placenta, according to Dr. Michal Elovitz, a preterm labor researcher and obstetrician at the University of Pennsylvania. This might, in theory, cause inflammation in utero that could be harmful to the developing fetal brain.

Or, the lipid nanoparticles might not cross the placenta, Dr. Elovitz says. It’s also possible the new vaccines could be totally safe in pregnancy, like the flu shot. We just don’t have the data yet.

“To avoid having pregnant people guess, we should be advocating for more preclinical and clinical research focused on pregnant patients,” she told me.

My bottom line: If I have the chance, I’ll gladly enroll in a clinical trial of a Covid-19 vaccine for pregnant people. It’s a choice that feels much more grounded in science than trying to figure this out on my own, because I’d be making it alongside the expertise of the scientists designing the trial.

I’d feel reassured that experts in immunology and pregnancy physiology had determined the safest trimester to get the vaccine. I’d feel reassured that they had done that using evidence from animal studies, and I’d feel reassured by the ethics board that approved the trial. It wouldn’t be a risk-free decision, but it would make me feel like it wasn’t a totally reckless one.

Until then, I’ll take care of my patients with my mask, my face shield, and my gloves, hoping I don’t get infected, thinking every day about my health and the health of my baby.

Dr. Mara Gordon is a family physician in Camden, N.J.

Fears of a ‘Twindemic’ Recede as Flu Lies Low

Fears of a ‘Twindemic’ Recede as Flu Lies Low

Despite early worries, flu patients are not competing with Covid-19 patients for ventilators, and the threat of dueling outbreaks may be waning.

A free flu shot administered at Comerica Park in Detroit, Mich., last month.
A free flu shot administered at Comerica Park in Detroit, Mich., last month.Credit…Seth Herald/Agence France-Presse — Getty Images
Donald G. McNeil Jr.

  • Dec. 13, 2020, 5:00 a.m. ET

Despite the horrifying surge of Covid-19 cases and deaths in the United States right now, one bit of good news is emerging this winter: It looks unlikely that the country will endure a “twindemic” of both flu and the coronavirus at the same time.

That comes as a profound relief to public health officials who predicted as far back as April that thousands of flu victims with pneumonia could pour into hospitals this winter, competing with equally desperate Covid-19 pneumonia victims for scarce ventilators.

“Overall flu activity is low, and lower than we usually see at this time of year,” said Dr. Daniel B. Jernigan, director of the influenza division of the Centers for Disease Control and Prevention. “I don’t think we can definitively say there will be no twindemic; I’ve been working with flu for a long time, and I’ve been burned. But flu is atypically low.”

Since September, the C.D.C. “FluView” — its weekly report on influenza surveillance — has shown all 50 states in shades of green and chartreuse, indicating “minimal” or “low” flu activity. Normally by December, at least some states are painted in oranges and reds for “moderate” and “high.”

(For one puzzling week in November, Iowa stood out in dark burgundy, indicating “very high” flu levels. But that turned out to be a reporting error, Dr. Jernigan said.)

Of 232,452 swabs from across the country that have been tested for flu, only 496, or 0.2 percent, have come up positive.

That has buoyed the spirits of flu experts.

Dr. William Schaffner, medical director for the National Foundation for Infectious Diseases, which promotes flu shots, said he was recently on a telephone discussion with other preventive medicine specialists. “Everybody was in quiet awe about how low flu is,” he said. “Somebody said: ‘Shh, don’t talk about it. The virus will hear us.’”

Flu numbers are likely to remain low for many more weeks, predicted Kinsa Health, a company that uses cellphone-connected thermometers and historical databases to forecast flu trends.

“Going forward, we don’t expect influenza-like illness to go high,” said Inder Singh, Kinsa’s founder and chief executive. “It looks like the twindemic isn’t going to happen.”

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By The New York Times | Source: Kinsa

A combination of factors is responsible for the remarkably quiet flu season, experts said.

In the Southern Hemisphere, where winter stretches from June through August, widespread mask-wearing, rigorous lockdowns and other precautions against Covid-19 transmission drove flu down to record-low levels. Southern Hemisphere countries help “reseed” influenza viruses in the Northern Hemisphere each year, Dr. Jernigan said.

Also, to keep Covid-19 out, New Zealand and Australia have closed their borders either to all noncitizens or to Americans, so there has been very little air traffic from those Southern Hemisphere countries.

In the United States, the cancellation of large indoor gatherings, closings of schools and use of masks to prevent coronavirus transmission have also driven down levels of all respiratory diseases, including influenza.

In addition, Dr. Jernigan said, a “phenomenal number” of flu shots were manufactured and shipped to pharmacies, hospitals and doctors’ office in August, a month earlier than usual.

As of late November, 188 million doses had been shipped; the old record was 175 million doses shipped last year. Spot shortages were quickly reported in some cities, so experts assumed that large numbers of Americans took them.

However, there is not yet enough data to confirm that assumption. According to a preliminary tally released Dec. 9, about 70 million adults had received the shots through pharmacies or doctors’ offices as of mid-November, compared with 58 million last year.

Although that appears to be a substantial increase, the C.D.C. does not know how many Americans who normally get their flu shots at work were unable to do so this year because of stay-at-home orders, said Dr. Ram Koppaka, the agency’s associate director for adult immunization. There was a big increase in flu shots delivered by pharmacies, and that may represent people who normally would have received the shots at work.

“The best we can say is that it appears that we are now about where we were last year,” Dr. Koppaka said.

Given that vaccines were available early, he added: “I’m disappointed that it’s not better than it is. We need to keep telling people that it’s not too late to get a flu shot.”

Normally, about 80 percent of all adults who get flu shots have had them by the end of November. But about nine million doses of vaccines that were meant for uninsured adults, and which the federal government purchased this year out of fear of a “twindemic,” are still being delivered, Dr. Koppaka said.

The finally tally of how many shots were taken will not be available until summer, after the flu season is over, he said.

Nonetheless, even the preliminary data showed disturbing trends in two important target groups: pregnant women and children. Only 54 percent of pregnant women have received flu vaccine this year, compared with 58 percent by this time last year. And, although about 48 percent of all children got flu shots both last year and this year, the percentage of Black children who got them dropped substantially this year, by 11 percentage points.

Dr. Koppaka said he could not yet account for those drops in coverage. Pregnant women might have been afraid to go to doctors or pharmacies for fear of getting Covid-19, and many Black children might have been missed because public schools that offer vaccines were closed — but that was just speculation, he emphasized.

Although Dr. Koppaka strongly encouraged unvaccinated Americans to get flu shots, the threat of a two-headed pandemic monster appears to be fading.

Because of the coronavirus pandemic, the C.D.C. is not currently posting forecasts on its FluSight page, where it predicts the future course of the flu season.

Kinsa Health, by contrast, is predicting that flu will stay at historic lows through February, when the season typically peaks. The company has a record of accurately predicting flu seasons several weeks ahead of the C.D.C.

C.D.C. surveillance data is based on weekly reports from doctors’ offices and hospitals noting the percentage of patient visits that are for flu symptoms. Because there are delays in reporting, sometimes for weeks, there is a lag between the time a flu arrives in a county and the agency’s confirmation that it is there.

Also, people who catch flu but never see a doctor are not captured in the C.D.C.’s surveillance net. People avoid doctors for many reasons, including a lack of insurance or because, this year, they are afraid of catching the coronavirus.

Kinsa receives about 100,000 readings each day from about two million thermometers connected to smartphones; the company claims it can detect local fever spikes down to the ZIP code level.

Both Covid-19 and flu can drive up the number of reported fevers, but flu outbreaks can be distinguished from Covid ones, Mr. Singh said.

The company has access to decades of historical flu data from 600 cities across the country, and there are patterns to how flu typically spreads in each city based on climate and population density, said Samuel D. Chamberlain, the company’s chief data scientist.

Also, because everyone is susceptible to the new coronavirus, Covid fevers surge and spread much faster across ZIP codes than do those caused by colds and flu, Mr. Singh said.

Moreover, users are asked to enter all their symptoms in the Kinsa app. Loss of smell and taste is a common Covid-19 symptom. Making things even simpler, the app asks users if they have had a positive coronavirus or flu test.

Currently, flu is at less than half its typical level for early December, Mr. Singh said. By February, when cases typically shoot to a sharp peak, its numbers should be down to about one-quarter of a typical seasonal apex, he predicted.

“In theory, the flu virus could be taking a year off,” said Dr. Arthur Reingold, head of epidemiology at the School of Public Health of the University of California, Berkeley.

He recently asked a friend who was treating Covid-19 cases at the University of California, San Francisco, hospital how many flu cases she had seen this year.

“The answer was zero,” he said. “That’s a relief, and certainly a relief to my friends who do clinical work.”

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Flu Vaccine Has Added Benefits for People With Diabetes

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People with Type 2 diabetes may get an added benefit from the flu vaccine: a reduced risk of cardiovascular disease.

British researchers studied 124,503 people with Type 2 diabetes over a seven-year period. About two-thirds of them had been vaccinated against flu.

After controlling for sex, age, smoking, body mass index, hypertension, medications and other health and behavioral factors, they found that people with Type 2 diabetes who had gotten the flu vaccine had a 30 percent lower risk of stroke, a 22 percent lower risk of heart failure and a 24 percent lower risk of dying from all causes. They also had a slightly lower, but statistically insignificant, risk for heart attack.

The lead author, Dr. Eszter P. Vamos, a clinical fellow at Imperial College London, said that people with diabetes are already at high risk for cardiovascular disease, and flu is particularly dangerous for them.

“The flu vaccine is largely underused among people with chronic illnesses,” she said. “It’s really important that people with diabetes receive their annual flu vaccine.”

The study, published in the Canadian Medical Association Journal, had a large sample and a long follow-up time, which give it considerable strength. Still, the authors acknowledge they were unable to account for all of the factors that could make people who get a flu shot different from people who do not.

Flu Vaccine in Pregnancy Offers Brief Protection of Babies

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Unborn babies are temporarily protected by their mother’s flu shot, but that immunity fades within weeks after birth, a new study found.

In a randomized, double-blind placebo-controlled study, researchers measured the efficacy of the flu vaccine on the unborn children of vaccinated pregnant women by comparing rates of disease and levels of antibodies in 1,026 infants born to vaccinated women and 1,023 controls born to unvaccinated mothers. The study, which was paid for by the Gates Foundation, is online in JAMA Pediatrics.

The vaccine was about 86 percent effective until the babies were 8 weeks old. But between 8 and 24 weeks, its power dropped rapidly, and the effect of the vaccine became statistically insignificant.

The lead author, Marta C. Nunes, a researcher at the University of Witwatersrand in Johannesburg, stressed that vaccination during pregnancy is nevertheless essential.

“It’s still important to vaccinate women during pregnancy,” she said. “Pregnant women are a high-risk group, and vaccinating them protects them as well as their babies.”

Finding a vaccine for pregnant women that confers long-lasting immunity on the baby is important because no flu vaccine is approved for babies under the age of 6 months.

“We have to work on creating vaccines that work in babies or that are more immunogenic in the mother so that her antibodies last longer,” she said.

Flu Shots Protect Babies, Too

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Here’s one more reason pregnant women should get a flu shot: It not only protects mothers, but a large study suggests it prevents flu in the infant, too.

Giving babies under 6 months old a flu vaccination does not work. Their immune systems are too immature to mount an effective response. But infants can get the flu, and it can have serious, even deadly, consequences.

Researchers used data on live births among women in a large health maintenance organization, including 23,847 babies born to mothers who had been vaccinated against the flu and 225,540 born to mothers who were not vaccinated. The study, published in Pediatrics, was carried out during the H1N1 flu pandemic of 2009-10.

Babies of unvaccinated women were 70 percent more likely to have a laboratory-confirmed case of flu, and 81 percent more likely to be hospitalized for flu before they were 6 months old.

The lead author of the study, Dr. Julie H. Shakib, an assistant professor of pediatrics at the University of Utah, said that after the 2009-10 pandemic, rates of vaccination of pregnant women went up sharply. In the 2013-14 season, more than 50 percent of pregnant women were vaccinated.

“We were encouraged to see the increase after the pandemic,” she said. “That’s when the public became aware of how much of a risk there was, and when obstetrics practices started delivering the vaccine as a routine part of care.”

Flu Shot During Pregnancy May Reduce Risk of Stillbirths

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Flu vaccination during pregnancy may reduce the risk of stillbirth, a new study reports.

Researchers studied birth and maternal vaccination records for 58,008 pregnancies in Western Australia during the 2012 and 2013 flu seasons. There were 5,076 births to women who had had the flu vaccine at some point during pregnancy, and 52,932 births to unvaccinated mothers.

After adjusting for maternal age, socioeconomic status, diabetes, hypertension and other health and behavioral characteristics, they found that the risk of stillbirth was 51 percent lower in vaccinated women than in unvaccinated ones.

The researchers acknowledge that the study, in Clinical Infectious Diseases, is observational and does not prove cause and effect, and that the results may not be generalizable to other populations or other flu seasons.

The Centers for Disease Control and Prevention recommends the flu vaccine during pregnancy, but more than half of all pregnant women in the United States are unvaccinated.

The lead author, Annette K. Regan of the Western Australia health department, said that pregnant women go unvaccinated for two main reasons: they are unaware of its importance and their doctor does not recommend it, or they fear it will harm the baby.

“We hope,” she continued, “that these results show not only pregnant women but also their providers that flu vaccination is safe during pregnancy and has major benefits for both mother and infant.”