Tagged Immune System

Vaccine Hesitancy in Cancer Patients

Living With Cancer

Vaccine Hesitancy in Cancer Patients

“If I accept the vaccine,” one cancer patient says, “it will be with a strong feeling of guilt that at best I will be prolonging my life for a few months or years.”

Credit…Celia Jacobs

  • Feb. 25, 2021, 5:00 a.m. ET

Do the vaccines against the coronavirus offer cancer patients the same hope that they hold out to healthy people? The women in my cancer support group expressed hesitancy as the vaccines started to be administered to health care workers.

Lucy Cherbas, in chemotherapy for recurrent ovarian cancer and in the over-70 population slated to receive the vaccine next, described the moral impediment that some healthy people also confront in a different variant.

“If I accept the vaccine,” she said, “it will be with a strong feeling of guilt that at best I will be prolonging my life for a few months or years, while others behind me in line still have full lives to live if they don’t succumb to Covid-19.”

Lucy’s altruism reminds us how many people have responded to the pandemic with grace and grit. I talked about her guilt with Dr. Timothy Lahey, a medical ethicist and infectious disease specialist at the University of Vermont Medical Center. He pointed out that at a personal level, “Lucy has no duty to endanger herself for others.” As long as she meets vaccine eligibility criteria, he said, “she should feel no compunction about claiming her vaccine.”

According to Dr. Lahey, “altruism is admirable because it is not compulsory.”

Even at a population level, with vaccine prioritization designed to minimize death and suffering, Lucy has “every right to trust the system and receive the vaccine when her number is called.” Of course, she can give up her place, but, Dr. Lahey said, “such a decision would do little to improve the efficiency of the overall distribution system.”

Lucy was also concerned about the physical issues that play a more prominent role in medical conversations. Because she is on a chemo drug that kills dividing cells, Lucy worried that the vaccine would be ineffective. “The development of an immune response involves a lot of cell division, and that seems unlikely to happen in the presence of anti-mitotic chemo agents,” she said. (Before she retired, Lucy was a molecular geneticist.) Since her oncologist continued to advise her to take the vaccine, Lucy has overcome her misgivings and has made an appointment.

Like Lucy, cancer patients need to discuss their unique cases with their physicians. According to Dr. Otis Brawley, past medical and scientific officer of the American Cancer Society and currently a professor of oncology at Johns Hopkins University, “no guidance has come out from the usual nongovernmental groups.”

Lucy Cherbas, center, in a pre-pandemic trip to Fenway Park, with her daughter Katherine Cherbas and her grandson Orlando Shin.Credit…Katherine Cherbas

He added that authorities like the Food and Drug Administration, the Centers for Disease Control and Prevention and the Medical Research Council of Britain “leave it up to individual doctors, but suggest that it should be safe.”

Ideally, those cancer patients who want the shot could get it at their cancer centers rather than in a mass distribution site. But a bumpy rollout and age restrictions have frustrated many people with cancer. Still, if the shot is offered, Dr. Brawley recommends it to his patients in active therapy and to those in follow-up. Certainly, they may not have as strong a response as someone who has an intact immune system; however, they will get some protection and will not be harmed because the current vaccines from Moderna and Pfizer are not produced from live virus (as measles, rubella, mumps and smallpox had been). Live virus vaccines must be avoided by the highly immunocompromised.

The Moderna and Pfizer coronavirus vaccines, Dr. Brawley explains, are made from messenger ribonucleic acid, or mRNA, by means of a new technology. Its genetic material causes the vaccinated person to create the same proteins that are found in the spikes of the novel coronavirus.

“The vaccinated person’s immune system then recognizes these proteins as foreign and produces antibodies against them,” Dr. Brawley said. “Another immune cell called a dendritic cell also records the proteins as foreign.”

Dr. William Nelson, director of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, agreed that “the worst that could happen” to cancer patients inoculated with the coronavirus vaccine “is a poor response.” The poorest responses will probably occur with people in treatment for B-cell lymphomas and multiple myeloma, he explained, because regimens for these diseases often involve agents targeting antibody-producing cells in the body. “For folks undergoing bone marrow transplants,” Dr. Nelson advised, vaccinations should probably be timed at three to six months after the transplant to ensure that immune recovery has occurred.

As important as the vaccines are, Dr. Nelson urged people with cancer as well as their families and friends to “remain vigilant about mask-wearing, social distancing, hand washing, etc.” Because cancer patients often experience low white-blood cell counts, their symptoms — fever, muscle aches, headache, dry cough — can be indistinguishable from those of Covid-19. “Now these patients will also need to be rapidly tested for the coronavirus and isolated in a suitable facility to get their intravenous antibiotics infused.”

When the health authorities in my state, Indiana, announced they would inoculate people over 70, I had no problem signing up online for an appointment. When I went for my first shot at a small medical facility, it was abuzz with people buoyed by high hopes for widespread, so-called herd immunity. My own optimism was shadowed by periodic news stories this winter about mask-less receptions, rallies, protests, parties and raves, and by personal conversations with people scared of inoculation in general.

As Eula Biss explained in her brilliant pre-pandemic book “On Immunity,” fear of the government, of the medical establishment, and of public intrusions into the private body can inhibit the collective trust that achieving immunity requires. Because fearfulness often afflicts cancer patients, they might be especially susceptible to these sorts of trepidations.

In a period of rampant disinformation, anti-vaccine campaigners have emerged to decry what they call a “scamdemic.” They will feed and fuel vaccine anxiety unless they are vigilantly countered by scientific authorities in the media.

Studies Suggest People Who Had Covid-19 Should Get Single Vaccine Dose

People Who Have Had Covid Should Get Single Vaccine Dose, Studies Suggest

New studies show that one shot of a vaccine can greatly amplify antibody levels in those who have recovered from the coronavirus.

A nurse supervisor prepared a dose of the Pfizer-BioNTech vaccine at a mass vaccination site in Hartford, Conn., this month.
A nurse supervisor prepared a dose of the Pfizer-BioNTech vaccine at a mass vaccination site in Hartford, Conn., this month.Credit…Christopher Capozziello for The New York Times
Apoorva Mandavilli

  • Feb. 19, 2021Updated 11:49 a.m. ET

Nearly 30 million people in the United States — and probably many others whose illnesses were never diagnosed — have been infected with the coronavirus so far. Should these people still be vaccinated?

Two new studies answer that question with an emphatic yes.

In fact, the research suggests that for these people just one dose of the vaccine is enough to turbocharge their antibodies and destroy the coronavirus — and even some more infectious variants.

The results of these new studies are consistent with the findings of two others published over the past few weeks. Taken together, the research suggests that people who have had Covid-19 should be immunized — but a single dose of the vaccine may be enough.

“I think it’s a really strong rationale for why people who were previously infected with Covid should be getting the vaccine,” said Jennifer Gommerman, an immunologist at the University of Toronto who was not involved in the new research.

A person’s immune response to a natural infection is highly variable. Most people make copious amounts of antibodies that persist for many months. But some people who had mild symptoms or no symptoms of Covid-19 produce few antibodies, which quickly fall to undetectable levels.

The vaccines “even the playing field,” Dr. Gommerman said, so that anyone who has recovered from Covid-19 produces enough antibodies to protect against the virus.

The latest study, which has not yet been published in a scientific journal, analyzed blood samples from people who have had Covid-19. The findings suggested that their immune systems would have trouble fending off B.1.351, the coronavirus variant first identified in South Africa.

But one shot of either the Pfizer-BioNTech or Moderna vaccine significantly changed the picture: It amplified the amount of antibodies in their blood by a thousandfold — “a massive, massive boost,” said Andrew T. McGuire, an immunologist at the Fred Hutchinson Cancer Research Center in Seattle, who led the study.

Flush with antibodies, samples from all of the participants could neutralize not only B.1.351, but also the coronavirus that caused the SARS epidemic in 2003.

In fact, the antibodies seemed to perform better than those in people who had not had Covid and had received two doses of a vaccine. Multiple studies have suggested that the Pfizer-BioNTech and Moderna vaccines are about five times less effective against the variant.

A Covid-19 patient in the intensive care unit of Marian Regional Medical Center in Santa Maria, Calif., this month.
A Covid-19 patient in the intensive care unit of Marian Regional Medical Center in Santa Maria, Calif., this month.Credit…Daniel Dreifuss for The New York Times

The researchers obtained blood samples from 10 volunteers in the Seattle Covid Cohort Study who were vaccinated months after contracting the coronavirus. Seven of the participants received the Pfizer-BioNTech vaccine and three received the Moderna vaccine.

Blood taken about two to three weeks after vaccination showed a significant jump in the amounts of antibodies compared with the samples collected before vaccination. The researchers don’t yet know how long the increased amount of antibodies will persist, but “hopefully, they’ll last a long time,” Dr. McGuire said.

The researchers also saw increases in immune cells that remember and fight the virus, Dr. McGuire said. “It looks pretty clear that we’re boosting their pre-existing immunity,” he said.

In another new study, researchers at New York University found that a second dose of the vaccine did not add much benefit at all for people who have had Covid-19 — a phenomenon that has also been observed with vaccines for other viruses.

In that study, most people had been infected with the coronavirus eight or nine months earlier, but saw their antibodies increase by a hundredfold to a thousandfold when given the first dose of a vaccine. After the second dose, however, the antibody levels did not increase any further.

“It’s a real testament to the strength of the immunologic memory that they get a single dose and have a huge increase,” said Dr. Mark J. Mulligan, director of the N.Y.U. Langone Vaccine Center and the study’s lead author.

In some parts of the world, including the United States, a significant minority of the population has already been infected, Dr. Mulligan noted. “They definitely should be vaccinated,” he said.

It’s unclear whether the thousandfold spike in antibody levels recorded in the lab will occur in real-life settings. Still, the research shows that a single shot is enough to increase the levels of antibodies significantly, said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York.

Dr. Krammer led another of the new studies, which showed that people who have had Covid-19 and received one dose of a vaccine experienced more severe side effects from the inoculation and had more antibodies compared with those who had not been infected before.

“If you put all four papers together, that’s providing pretty good information about people who already had an infection only needing one vaccination,” Dr. Krammer said.

He and other researchers are trying to persuade scientists at the Centers for Disease Control and Prevention to recommend only one dose for those who have recovered from Covid-19.

A woman receives a vaccine at a drive-through site in Hartford.Credit…Christopher Capozziello for The New York Times

Ideally, those people should be monitored after the first shot in case their antibody levels plummet after some weeks or months, said Dennis R. Burton, an immunologist at the Scripps Research Institute in La Jolla, Calif.

The fact that the supercharged antibodies observed in the new study can fight the 2003 SARS virus suggests that a single dose of the vaccine may have prompted the volunteers’ bodies to produce “broadly neutralizing antibodies” — immune molecules capable of attacking a broad range of related viruses, Dr. Burton said.

He and other scientists have for decades investigated whether broadly neutralizing antibodies can tackle multiple versions of H.I.V. at once. H.I.V. mutates faster than any other virus and quickly evades most antibodies.

The new coronavirus mutates much more slowly, but there are now multiple variants of the virus that seem to have evolved to be more contagious or to thwart the immune system. The new study may provide clues on how to make a single vaccine that stimulates the production of broadly neutralizing antibodies that can destroy all variants of the coronavirus, Dr. Burton said.

Without such a vaccine, scientists will need to tweak the vaccines every time the virus changes significantly. “You’re stuck in a kind of Whac-a-Mole approach,” he said. It will probably take many months if not longer to develop and test that sort of vaccine against the coronavirus, but “that’s the longer-term way to approach this virus.”

People Who Have Had Covid Should Get Single Vaccine Dose, Studies Suggest

People Who Have Had Covid Should Get Single Vaccine Dose, Studies Suggest

New studies show that one shot of a vaccine can greatly amplify antibody levels in those who have recovered from the coronavirus.

A nurse supervisor prepared a dose of the Pfizer-BioNTech vaccine at a mass vaccination site in Hartford, Conn., this month.
A nurse supervisor prepared a dose of the Pfizer-BioNTech vaccine at a mass vaccination site in Hartford, Conn., this month.Credit…Christopher Capozziello for The New York Times
Apoorva Mandavilli

  • Feb. 19, 2021, 9:49 a.m. ET

At least 30 million people in the United States — and probably many others whose illnesses were never diagnosed — have been infected with the coronavirus so far. Should these people still be vaccinated?

Two new studies answer that question with an emphatic yes.

In fact, the research suggests that for these people just one dose of the vaccine is enough to turbocharge their antibodies and destroy the coronavirus — and even some more infectious variants.

The results of these new studies are consistent with the findings of two others published over the past few weeks. Taken together, the research suggests that people who have had Covid-19 should be immunized — but a single dose of the vaccine may be enough.

“I think it’s a really strong rationale for why people who were previously infected with Covid should be getting the vaccine,” said Jennifer Gommerman, an immunologist at the University of Toronto who was not involved in the new research.

A person’s immune response to a natural infection is highly variable. Most people make copious amounts of antibodies that persist for many months. But some people who had mild symptoms or no symptoms of Covid-19 produce few antibodies, which quickly fall to undetectable levels.

The vaccines “even the playing field,” Dr. Gommerman said, so that anyone who has recovered from Covid-19 produces enough antibodies to protect against the virus.

The latest study, which has not yet been published in a scientific journal, analyzed blood samples from people who have had Covid-19. The findings suggested that their immune systems would have trouble fending off B.1.351, the coronavirus variant first identified in South Africa.

But one shot of either the Pfizer-BioNTech or Moderna vaccine significantly changed the picture: It amplified the amount of antibodies in their blood by a thousandfold — “a massive, massive boost,” said Andrew T. McGuire, an immunologist at the Fred Hutchinson Cancer Research Center in Seattle, who led the study.

Flush with antibodies, samples from all of the participants could neutralize not only B.1.351, but also the coronavirus that caused the SARS epidemic in 2003.

In fact, the antibodies seemed to perform better than those in people who had not had Covid and had received two doses of a vaccine. Multiple studies have suggested that the Pfizer-BioNTech and Moderna vaccines are about five times less effective against the variant.

A Covid-19 patient in the intensive care unit of Marian Regional Medical Center in Santa Maria, Calif., this month.
A Covid-19 patient in the intensive care unit of Marian Regional Medical Center in Santa Maria, Calif., this month.Credit…Daniel Dreifuss for The New York Times

The researchers obtained blood samples from 10 volunteers in the Seattle Covid Cohort Study who were vaccinated months after contracting the coronavirus. Seven of the participants received the Pfizer-BioNTech vaccine and three received the Moderna vaccine.

Blood taken about two to three weeks after vaccination showed a significant jump in the amounts of antibodies compared with the samples collected before vaccination. The researchers don’t yet know how long the increased amount of antibodies will persist, but “hopefully, they’ll last a long time,” Dr. McGuire said.

The researchers also saw increases in immune cells that remember and fight the virus, Dr. McGuire said. “It looks pretty clear that we’re boosting their pre-existing immunity,” he said.

In another new study, researchers at New York University found that a second dose of the vaccine did not add much benefit at all for people who have had Covid-19 — a phenomenon that has also been observed with vaccines for other viruses.

In that study, most people had been infected with the coronavirus eight or nine months earlier, but saw their antibodies increase by a hundredfold to a thousandfold when given the first dose of a vaccine. After the second dose, however, the antibody levels did not increase any further.

“It’s a real testament to the strength of the immunologic memory that they get a single dose and have a huge increase,” said Dr. Mark J. Mulligan, director of the N.Y.U. Langone Vaccine Center and the study’s lead author.

In some parts of the world, including the United States, a significant minority of the population has already been infected, Dr. Mulligan noted. “They definitely should be vaccinated,” he said.

It’s unclear whether the thousandfold spike in antibody levels recorded in the lab will occur in real-life settings. Still, the research shows that a single shot is enough to increase the levels of antibodies significantly, said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York.

Dr. Krammer led another of the new studies, which showed that people who have had Covid-19 and received one dose of a vaccine experienced more severe side effects from the inoculation and had more antibodies compared with those who had not been infected before.

“If you put all four papers together, that’s providing pretty good information about people who already had an infection only needing one vaccination,” Dr. Krammer said.

He and other researchers are trying to persuade scientists at the Centers for Disease Control and Prevention to recommend only one dose for those who have recovered from Covid-19.

A woman receives a vaccine at a drive-through site in Hartford.Credit…Christopher Capozziello for The New York Times

Ideally, those people should be monitored after the first shot in case their antibody levels plummet after some weeks or months, said Dennis R. Burton, an immunologist at the Scripps Research Institute in La Jolla, Calif.

The fact that the supercharged antibodies observed in the new study can fight the 2003 SARS virus suggests that a single dose of the vaccine may have prompted the volunteers’ bodies to produce “broadly neutralizing antibodies” — immune molecules capable of attacking a broad range of related viruses, Dr. Burton said.

He and other scientists have for decades investigated whether broadly neutralizing antibodies can tackle multiple versions of H.I.V. at once. H.I.V. mutates faster than any other virus and quickly evades most antibodies.

The new coronavirus mutates much more slowly, but there are now multiple variants of the virus that seem to have evolved to be more contagious or to thwart the immune system. The new study may provide clues on how to make a single vaccine that stimulates the production of broadly neutralizing antibodies that can destroy all variants of the coronavirus, Dr. Burton said.

Without such a vaccine, scientists will need to tweak the vaccines every time the virus changes significantly. “You’re stuck in a kind of Whac-a-Mole approach,” he said. It will probably take many months if not longer to develop and test that sort of vaccine against the coronavirus, but “that’s the longer-term way to approach this virus.”

Covid Vaccines for Kids Are Coming, but Not for Many Months

Covid Vaccines for Kids Are Coming, but Not for Many Months

Pfizer and Moderna are testing their vaccines on children 12 and older and hope to have results by the summer.

A 15-year-old participating in Moderna’s teen Covid vaccine trial received a shot in Houston this month.
A 15-year-old participating in Moderna’s teen Covid vaccine trial received a shot in Houston this month.Credit…Brandon Thibodeaux for The New York Times
Apoorva Mandavilli

  • Feb. 12, 2021, 5:00 a.m. ET

As adults at high risk for Covid-19 line up to be immunized against the coronavirus, many parents want to know: When will my child get a vaccine?

The short answer: Not before late summer.

Pfizer and Moderna have enrolled children 12 and older in clinical trials of their vaccines and hope to have results by the summer. Depending on how the vaccines perform in that age group, the companies may then test them in younger children. The Food and Drug Administration usually takes a few weeks to review data from a clinical trial and authorize a vaccine.

Three other companies — Johnson & Johnson, Novavax and AstraZeneca — also plan to test their vaccines in children, but are further behind.

When researchers test drugs or vaccines in adults first, they typically then move down the age brackets, watching for any changes in the effective dose and for unexpected side effects.

“It would be pretty unusual to start going down into children at an early stage,” said Dr. Emily Erbelding, an infectious diseases physician at the National Institutes of Health who oversees testing of Covid-19 vaccines in special populations.

Some vaccines — those that protect against pneumococcal or meningococcal bacteria or rotavirus, for example — were tested in children first because they prevent pediatric diseases. But it made sense for coronavirus vaccines to be first tested in and authorized for adults because the risk of severe illness and death from Covid-19 increases sharply with age, said Paul Offit, a professor at the University of Pennsylvania and a member of the F.D.A.’s vaccine advisory panel.

“We’re trying to save lives, keep people out of the I.C.U., keep them from dying,” Dr. Offit said. That means prioritizing vaccines for the oldest people and for those with underlying conditions.

People younger than 21 account for about one-quarter of the population in the United States, but they make up less than 1 percent of deaths from Covid-19. Still, about 2 percent of children who get Covid-19 require hospital care, and at least 227 children in the United States have died of the disease.

“It is a significant disease in children, just not necessarily when you compare it to adults,” said Dr. Kristin Oliver, a pediatrician and vaccine expert at Mount Sinai Hospital in New York.

Children will also need to be vaccinated in order for the United States to approach herd immunity — that long-promised goal at which the pandemic slows to a halt because the virus runs out of people to infect.

Scientists have estimated that 70 to 90 percent of the population might need to be immunized against the coronavirus to reach herd immunity, especially with more contagious variants expected to circulate widely in the country.

“Not all adults can get the vaccine because there’s some reluctance, or there’s maybe even some vulnerable immune systems that just don’t respond,” Dr. Erbelding said. “I think we have to include children if we’re going to get to herd immunity.”

It will also be important to immunize children in racial and ethnic populations that are hit hardest by the pandemic, she added.

Abhinav, 12, a participant in the Pfizer vaccine trial at Cincinnati Children’s Hospital last month.
Abhinav, 12, a participant in the Pfizer vaccine trial at Cincinnati Children’s Hospital last month.Credit…Cincinnati Children’s Hospital

Pfizer and Moderna’s clinical trials in adults each enrolled about 50,000 participants. They had to be that large in order to show significant differences between the volunteers who received a vaccine and those who got a placebo. But because it is rarer for children to become seriously ill with Covid-19, that kind of trial design in children would not be feasible, because it would require many more participants to show an effect.

Instead, the companies will look at vaccinated children for signs of a strong immune response that would protect them from the coronavirus.

The Pfizer-BioNTech vaccine was authorized in December for anyone 16 and older. The company has continued its trial with younger volunteers, recruiting 2,259 adolescents from 12 to 15 years of age. Teenagers are roughly twice as likely to be infected with the coronavirus as younger children, according to the Centers for Disease Control and Prevention.

Results from that trial should be available by summer, said Keanna Ghazvini, a spokeswoman for Pfizer.

“Moving below 12 years of age will require a new study and potentially a modified formulation or dosing schedule,” Ms. Ghazvini said. Those trials will most likely start later in the year, but the plans will be made final after the company has data from older children, she added.

Moderna’s vaccine, which was also authorized in December, is on a similar track for pediatric testing. In December, the company began testing adolescents ages 12 through 17, and plans to enroll 3,000 volunteers in this age group. The company expects results “around midyear 2021,” said Colleen Hussey, a spokeswoman for Moderna.

Based on the results, Moderna plans to assess the vaccine later this year in children between the ages of 6 months and 11 years.

Infants may have some antibodies at birth from vaccinated or infected mothers, but that maternal protection is unlikely to last through the first year of age. And with their relatively weak immune systems, babies might be particularly susceptible to infection if community transmission is high.

The trials will also assess the vaccine’s safety in children — and hopefully ease any fears that parents have. One-third of adults in the United States have said they do not plan to have their children immunized against the coronavirus, according to a recent poll conducted by Verywell Health.

Given the low risk of Covid-19 in children, some parents might be skeptical of the urgency to inoculate their children with a brand-new jab, Dr. Offit said. “For that reason, the vaccine would have to be held to a very high standard of safety,” he said.

More than 42 million people in the United States have been immunized so far, with few lasting side effects. And the F.D.A. has set up multiple systems to carefully monitor any serious reactions to the vaccine.

“They’re really looking at the data very, very closely,” Dr. Oliver said. “As a pediatrician and a mom, I have really good confidence that those systems work.”

Once a vaccine for children is available, schools can reintroduce extracurricular activities that involve close contact, like band practice, team sports and choir. But in the meantime, there is ample evidence that schools can reopen with other precautions in place, Dr. Oliver said.

“I don’t think we need to anticipate having a vaccine in order to open schools in the fall,” she said. “We should be planning now for opening schools.”

Dr. Oliver also urged parents to make sure children are immunized for other diseases. According to the C.D.C., orders for non-flu childhood vaccines through the Vaccines for Children Program are down approximately 10.3 million doses over all.

“Now’s the time to really catch up on missed doses of those vaccines,” she said. “Measles, HPV, tetanus boosters, pertussis boosters — all of that is really important.”

Childhood Colds Do Not Prevent Coronavirus Infection, Study Finds

Childhood Colds Do Not Prevent Coronavirus Infection, Study Finds

New research casts doubt on the idea that prior infections with garden-variety coronaviruses might shield some people, particularly children, amid the pandemic.

Drive-through coronavirus antibody testing last month in Los Angeles.
Drive-through coronavirus antibody testing last month in Los Angeles.Credit…Ringo Chiu/Agence France-Presse — Getty Images
Apoorva Mandavilli

  • Feb. 10, 2021, 5:00 a.m. ET

The theory was simple and compelling: Children are less vulnerable to the new coronavirus because they carry antibodies to other common coronaviruses that cause the common cold. The idea might also explain why some people infected with the new virus have mild symptoms while others — presumably without antibodies to common cold coronaviruses — are much more severely affected.

The notion gained traction particularly among people who claimed that this existing protection would swiftly bring human populations to herd immunity, the point at which a pathogen’s spread slows to a halt as it runs out of hosts to infect. A study in the journal Science, published in December, gave the hypothesis a strong boost.

But for all its appeal, the theory does not hold up, according to a new study published on Tuesday in the journal Cell. Based on carefully conducted experiments with live virus and with hundreds of blood samples drawn before and after the pandemic, the new research refutes the idea that antibodies to seasonal coronaviruses have any impact on the new coronavirus, called SARS-CoV-2.

“Going into this study, we thought we would learn that individuals that had pre-existing, pre-pandemic antibodies against SARS-CoV-2 would be less susceptible to infection and have less severe Covid-19 disease,” said Scott Hensley, an immunologist at the University of Pennsylvania. “That’s not what we found.”

He and his colleagues concluded that most people are exposed to seasonal coronaviruses by age 5. As a result, about one in five people carries antibodies that recognize the new coronavirus.

But these antibodies are not neutralizing — they cannot disarm the virus, nor do they mitigate the severity of symptoms following infection, the team found.

The researchers also compared antibodies to common cold coronaviruses in children and adults and found no difference in the amounts. By contrast, the study in Science had reported that about 5 percent of adults carried those antibodies, compared with 43 percent of children.

That study “reported very high levels of pre-pandemic cross-reactive neutralizing antibodies in kids, something that we did not find,” Dr. Hensley said. (“Cross-reactive” refers to antibodies able to attack similar sites on more than one type of virus.)

“I don’t have an explanation for the difference from the Science study, honestly,” he added.

Perhaps the difference in locations — Pennsylvania, in his study, versus Britain in the previous research — may explain some of the discrepancy, he said.

Other experts said they found Dr. Hensley’s study to be more convincing of the two and more consistent with circumstances in which large groups of people become infected with the new coronavirus.

Schoolchildren at the South Boston Catholic Academy in Boston gave themselves Covid-19 tests last month.
Schoolchildren at the South Boston Catholic Academy in Boston gave themselves Covid-19 tests last month.Credit…Allison Dinner/Reuters

For example, a single person infected with the new coronavirus at a Wisconsin summer camp set off an outbreak that affected 76 percent of the other attendees, noted John Moore, a virologist at Weill Cornell Medicine in New York.

Similarly, on a fishing trawler that left for sea from Seattle, only three sailors who had antibodies to the new coronavirus before the trip stayed virus-free. Those are not the infection rates you would see if protective antibodies were widely distributed in the population, Dr. Moore said.

“The idea that having the snuffles a while back somehow protects you from SARS-CoV-2 infection has always left me cold, but it’s been a persistent urban legend throughout the pandemic,” he said. “Hopefully, this new paper will finally cool everyone down and put such thoughts into the freezer.”

Experts also praised the new study’s careful and rigorous approach.

“It’s really nice to have a study that’s this well done,” said Shane Crotty, a virologist at the La Jolla Institute of Immunology in San Diego.

The theory that existing antibodies can protect people from the new virus “has definitely got a strong appeal because at first blush, it can explain a lot of the pandemic,” Dr. Crotty said. “But a beautiful idea doesn’t make it true.”

Dr. Hensley and his colleagues examined samples from 251 people who had donated blood to the University of Pennsylvania before the pandemic and then went on to develop Covid-19.

Those people carried levels of antibodies able to recognize the new coronavirus that were no different from those seen in blood samples drawn from 251 people who remained uninfected. And the levels showed no relationship to the clinical outcome in any of the patients.

“It’s hard to come by those kinds of samples — I was just impressed,” said Marion Pepper, an immunologist at the University of Washington in Seattle. “It’s like three different studies wrapped into one.”

The most important part of the coronavirus is the spike protein on its surface, which docks onto human cells. The spike is also the most distinctive part of the virus, so it makes sense that antibodies to seasonal viruses would be unlikely to recognize and disarm it, Dr. Pepper said.

“There are very specific parts of these viruses that are critical for infection, and most of this cross-reactivity isn’t directed to those parts,” she said.

But George Kassiotis, an immunologist at the Francis Crick Institute in London who led the study published in Science, disagreed with the conclusions of the new research. It “largely confirms rather than contradicts our main findings,” he said, adding that the new study was too small to rule out any role for existing antibodies.

But even if people really were carrying coronavirus antibodies from childhood infections, the protection they confer is not powerful enough to matter, said Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle.

“If there is no effect that is measurable in a study with hundreds of people in both the infected and uninfected groups, then the effect is certainly tiny,” Dr. Bloom said.

Most of the vaccines developed for the new coronavirus are focused on the spike protein. Some scientists have argued that antibodies to other parts of the virus may also be critical to protection. But the new study suggests that the other antibodies are of minimal importance in protecting people from SARS-CoV-2.

The experts all said the new study did not rule out a role for immune cells, called memory B cells and T cells, produced in response to seasonal coronaviruses. Those cells might recognize some parts of the new virus and attack it, easing the severity of symptoms.

Still, the cells would not prevent infection, Dr. Crotty said. When exposed to the new virus, the immune cells might be roused “fast enough that you would have an asymptomatic infection that you never noticed,” he said. “But no, they wouldn’t stop infection.”

Tests of T cells are laborious and expensive, so analyses of their contribution to immunity are not yet complete. In the meantime, the new study at least rules out a significant role for existing antibodies, Dr. Hensley said: “We’ve sort of written one chapter here, but there’s still so much to be learned.”

In the Vaccine Scramble, Cancer Patients Are Left Behind

In the Vaccine Scramble, Cancer Patients Are Left Behind

Those with compromised immune systems are often advised to get the shots under medical supervision, but their cancer centers can’t always provide them.

Credit…Lilli Carré
Dani Blum

  • Feb. 3, 2021, 9:52 a.m. ET

A doctor in Arizona says her cancer patients are so desperate to get vaccinated against Covid-19 that they plan to volunteer at a stadium vaccination site. A woman in New Jersey with colon cancer can’t sign up for a vaccine appointment because her cancer center, in New York, is authorized to vaccinate only state residents. A cancer patient in Maryland refreshes and refreshes her computer, but can’t find an available vaccination appointment.

Facing conflicting guidance and logistical chaos, many cancer patients are struggling to navigate the bumpy rollout of the Covid-19 vaccination campaign. Ideally, cancer patients who take immunosuppressant medications should receive vaccinations under the care of a doctor, or in a cancer center, where they can be closely monitored and encounter fewer people than they would at a mass distribution site. But the limited availability of the vaccine, plus the havoc and confusion surrounding the rollout, leaves patients grasping for answers.

“It’s really frustrating when you’re a stage four cancer patient and you can’t get on the list,” said Connie Johnson, 62. “Cancer is a life sentence. But Covid is a death sentence.”

Ideally, patients would receive the vaccines at cancer centers, said Dr. Steven Pergam, infection prevention director at Seattle Cancer Care Alliance and co-leader of the National Comprehensive Cancer Network’s Covid-19 vaccine committee. In addition to the potential of contracting Covid-19 and other pathogens at a mass vaccination site, cancer patients who suffer from fatigue may have trouble standing in line. But as vaccination efforts across the country shift to large-scale sites like stadiums, cancer centers may not have shots available.

“It becomes a really challenging experience for these patients to negotiate and navigate a complex system,” he said. He recommends that patients ask their doctors if there are any options, like a drive-through, at a vaccination site, and also encourage any eligible members of their household to get vaccinated.

Even when cancer centers do have vaccine doses available, the state-by-state nature of vaccination rules complicates patient care. Some major cancer centers cannot offer vaccines to patients from across state lines, said Dr. Tobias Hohl, chief of infectious disease service at Memorial Sloan Kettering Cancer Center in New York. He provides care to patients from throughout the tristate area, he said, and 10 percent of the center’s patients are international, but New York state rules authorize the center to treat only state residents. “It breaks our hearts,” he said. “It’s immensely frustrating to many providers.”

Ms. Johnson paused her chemotherapy treatment when she learned that vaccines were approved, hoping to optimize her immune response to the shot. She lives in Maricopa County, Ariz., which is currently vaccinating people in phase 1B. She’s in the next group, 1C. If she isn’t vaccinated in the next month, she said, she’ll have to resume chemotherapy, even though the treatment may weaken her immune system and potentially make the vaccine less effective for her. “I can’t wait that long,” she said. “I just have to hope it’s OK.”

Ms. Johnson is part of a Facebook group for cancer patients, many of whom express rage and frustration over the vaccine roll out. “It’s a full-time job just managing chemo and side effects,” she said. “To have to go through all of this confusion — I think a lot of them are going to throw up their hands.”

According to the American Cancer Society, initial studies testing the Covid-19 vaccines did not include people receiving treatments, like chemotherapy, that suppress the immune system. Of the people included in the Pfizer-BioNTech vaccine trials, 3.7 percent were identified to have a history of malignancy at the time of reporting, said Dr. Pergam, but the assumption is that they are patients with a history of cancer, like surgically cured melanoma, and not patients under active treatment. As a result, it’s not clear how cancer patients in active treatment will respond to the vaccine.

“This has been a complete — I won’t say disaster, but it’s been pretty close,” said Dr. Hanny Al-Samkari, hematologist and clinical investigator at the Massachusetts General Hospital and Harvard Medical School. Cancer patients are receiving “mixed messaging,” he said, and the guidance they get largely depends on their state. Every day he receives a deluge of messages from patients asking if they qualify to receive the vaccine yet (in his state, the answer is largely no). One drove four hours to find a vaccination site. “It’s the Wild West,” he said.

He urged cancer patients to consult with their doctors to coordinate the timing of the vaccine in line with their treatment, unless they are in remission, were treated a long time ago or are receiving only hormonal treatment for breast or prostate cancer, said Dr. Tomasz Beer, a professor at the Oregon Health and Science University’s School of Medicine and deputy director of the school’s Knight Cancer Institute.


Covid-19 Vaccines ›


Answers to Your Vaccine Questions

Currently more than 150 million people — almost half the population — are eligible to be vaccinated. But each state makes the final decision about who goes first. The nation’s 21 million health care workers and three million residents of long-term care facilities were the first to qualify. In mid-January, federal officials urged all states to open up eligibility to everyone 65 and older and to adults of any age with medical conditions that put them at high risk of becoming seriously ill or dying from Covid-19. Adults in the general population are at the back of the line. If federal and state health officials can clear up bottlenecks in vaccine distribution, everyone 16 and older will become eligible as early as this spring or early summer. The vaccine hasn’t been approved in children, although studies are underway. It may be months before a vaccine is available for anyone under the age of 16. Go to your state health website for up-to-date information on vaccination policies in your area

You should not have to pay anything out of pocket to get the vaccine, although you will be asked for insurance information. If you don’t have insurance, you should still be given the vaccine at no charge. Congress passed legislation this spring that bars insurers from applying any cost sharing, such as a co-payment or deductible. It layered on additional protections barring pharmacies, doctors and hospitals from billing patients, including those who are uninsured. Even so, health experts do worry that patients might stumble into loopholes that leave them vulnerable to surprise bills. This could happen to those who are charged a doctor visit fee along with their vaccine, or Americans who have certain types of health coverage that do not fall under the new rules. If you get your vaccine from a doctor’s office or urgent care clinic, talk to them about potential hidden charges. To be sure you won’t get a surprise bill, the best bet is to get your vaccine at a health department vaccination site or a local pharmacy once the shots become more widely available.

Probably not. The answer depends on a number of factors, including the supply in your area at the time you’re vaccinated. Check your state health department website for more information about the vaccines available in your state. The Pfizer and Moderna vaccines are the only two vaccines currently approved, although a third vaccine from Johnson & Johnson is on the way.

That is to be determined. It’s possible that Covid-19 vaccinations will become an annual event, just like the flu shot. Or it may be that the benefits of the vaccine last longer than a year. We have to wait to see how durable the protection from the vaccines is. To determine this, researchers are going to be tracking vaccinated people to look for “breakthrough cases” — those people who get sick with Covid-19 despite vaccination. That is a sign of weakening protection and will give researchers clues about how long the vaccine lasts. They will also be monitoring levels of antibodies and T cells in the blood of vaccinated people to determine whether and when a booster shot might be needed. It’s conceivable that people may need boosters every few months, once a year or only every few years. It’s just a matter of waiting for the data.

Employers do have the right to compel their workers to be vaccinated once a vaccine is formally approved. Many hospital systems, for example, require annual flu shots. But employees can seek exemptions based on medical reasons or religious beliefs. In such cases, employers are supposed to provide a “reasonable accommodation” — with a coronavirus vaccine, for example, a worker might be allowed to work if they wear a mask, or to work from home.

If you have other questions about the coronavirus vaccine, please read our full F.A.Q.

For instance, those who are on chemotherapy may have the best chances of mounting an immune response if the vaccine is given when their white blood cell counts are not at their lowest level, Dr. Beer said. Recommendations for patients with leukemia or lymphoma who are in treatment or had a recent bone marrow transplant are particularly complex and absolutely require consultation and coordination with an oncologist, he stressed.

While some may worry about the risks of encountering a crowd at a mass vaccination site, Dr. Al-Samkari advises patients to receive the doses wherever they are available, as long as they wear masks and keep their distance from other people in line. “Anxieties are clearly well-founded,” he said. “But we need to get shots in arms.”

In general, people with cancer should get the vaccine “as soon as they can, wherever they can,” said Dr. Carol Ann Huff, clinical director of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins and one of the authors of the National Comprehensive Cancer Network guidelines on Covid-19 vaccines for cancer patients. There are some caveats: Patients who receive a bone-marrow transplant or CAR-T therapy should wait at least three months before receiving the vaccine, she said.

But, depending on the level of virus transmission in a patient’s community, it might be safer to wait to receive the vaccine. If there’s a high level of transmission in the community, “the risks might outweigh the benefits of waiting,” Dr. Beer said. Patients with active cancer should connect with their oncologist before receiving the vaccine, he advised, unless they are in remission, were treated a long time ago or are receiving only hormonal treatment for breast or prostate cancer.

Those participating in cancer clinical trials have murkier guidance on vaccination. Allyson Harkey, 46, of Maryland, has stage four renal cancer and is participating in an immunotherapy trial; she said her doctor isn’t sure whether she should get the vaccine. The National Comprehensive Cancer Network’s guidelines broadly recommend patients receiving immunotherapy should get the vaccine as it becomes available, but should consult with their doctors beforehand since there’s such a variety of trials. She feels as if she is in a state of limbo, waiting for more information — a process made more frustrating by what she feels is a ticking clock. “My prognosis isn’t great. I probably have a few years left,” she said. “It’s really hard to spend this time, knowing I don’t have a lot of time left, just in my house.”

Had Covid? You May Need Only One Dose of Vaccine, Study Suggests

Had Covid? You May Need Only One Dose of Vaccine, Study Suggests

People who have already been sick with Covid-19 should still be vaccinated, experts say, but they may experience intense side effects even after one dose.

People who received Moderna’s Covid-19 vaccine sat in a waiting area at a vaccination site in San Diego, Calif. 
People who received Moderna’s Covid-19 vaccine sat in a waiting area at a vaccination site in San Diego, Calif. Credit…Ariana Drehsler for The New York Times

  • Feb. 1, 2021, 2:18 p.m. ET

Shannon Romano, a molecular biologist, came down with Covid late last March, about a week after she and her colleagues shut down their lab at Mount Sinai Hospital. A debilitating headache came first, followed by a fever that kept rising, and then excruciating body aches. “I couldn’t sleep. I couldn’t move,” she said. “Every one of my joints just hurt inside.”

It was not an experience she wanted to repeat — ever. So when she became eligible for the Covid-19 vaccine earlier this month, she got the shot.

Two days after her injection, she developed symptoms that felt very familiar. “The way my head hurt and the way my body ached was the same headache and body ache I had when I had Covid,” she said. She recovered quickly, but her body’s intense response to the jab caught her by surprise.

A new study may explain why Dr. Romano and many others who have had Covid report these unexpectedly intense reactions to the first shot of a vaccine. In a study posted online on Monday, researchers found that people who had previously been infected with the virus reported fatigue, headache, chills, fever, and muscle and joint pain after the first shot compared more frequently than did those who had never been infected. Covid survivors also had far higher antibody levels after both the first and second doses of the vaccine.

Based on these results, the researchers say, people who have had Covid-19 may need only one shot.

“I think one vaccination should be sufficient,” said Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai and an author on the study. “This would also spare individuals from unnecessary pain when getting the second dose and it would free up additional vaccine doses.”

While some scientists agree with his logic, others are more cautious. E. John Wherry, director of the University of Pennsylvania’s Institute for Immunology, said that before pushing for a change in policy, he would like to see data showing that those antibodies were able to stop the virus from replicating. “Just because an antibody binds to a part of the virus does not mean it’s going to protect you from being infected,” he said.

It might also be difficult to identify which people have previously been infected, he said. “Documenting that becomes a really potentially messy public health issue,” he said.

A dose of Pfizer’s vaccine was prepared at a vaccination site in Rohnert Park, Calif.
A dose of Pfizer’s vaccine was prepared at a vaccination site in Rohnert Park, Calif.Credit…Jim Wilson/The New York Times

Side effects after vaccination are entirely expected. They show that the immune system is mounting a response and will be better prepared to fight off an infection if the body comes into contact with the virus. The Pfizer and Moderna vaccines are particularly good at evoking a strong response. Most participants in the companies’ trials reported pain at the injection site, and more than half reported fatigue and headaches.

The clinical trials of the authorized vaccines from Pfizer and Moderna, which included more than 30,000 participants each, suggest that most people experience the worst side effects after the second jab. And in the Moderna study, people who had previously been infected actually had fewer side effects than those who hadn’t.

But anecdotally, researchers are hearing from a growing number of people like Dr. Romano who felt ill after one shot. “They describe these symptoms much more vigorously,” Dr. Wherry said.

That matches what Dr. Krammer and his colleagues found in their new study, which has not yet been published in a scientific journal. The researchers assessed symptoms after vaccination in 231 people, of whom 83 had previously been infected, and 148 had not. Both groups widely reported experiencing pain at the injection site after the first dose. But those who had been infected before more often reported fatigue, headache and chills.

The team also looked at how the immune system responded to the vaccine in 109 people — 68 of whom had not previously been infected and 41 who had — and found a more robust antibody response in the latter group. The numbers, however, are small, and so the study’s conclusions will need to be further investigated with more research, experts said.

It’s not necessarily surprising that previously infected individuals might experience more intense reactions. Both shots contain bits of genetic material that spur the body to manufacture spike proteins, the knobby protrusions on the coronavirus’s surface. People who have already been infected with the virus have immune cells that are primed to recognize these proteins. So when the proteins show up after vaccination, some of those immune cells go on the attack, causing people to feel sick.

Dr. Susan Malinowski, an ophthalmologist in Michigan who had Covid-19 in March, certainly felt like her body was under attack after she received the Moderna vaccine. She got the first shot before lunch on New Year’s Eve. By dinner, she was starting to feel ill. She spent the next two days miserable in bed.

“I had fevers. I had chills. I had night sweats. I had pain everywhere in my body,” she said. “I was actually more ill after the vaccine than I was with Covid.”

The entrance to a vaccination site in San Diego. Credit…Ariana Drehsler for The New York Times

Questions about more severe vaccine reactions in people who have already had Covid came up at a Jan. 27 meeting of an expert committee that advises the Centers for Disease Control and Prevention.


Covid-19 Vaccines ›


Answers to Your Vaccine Questions

Currently more than 150 million people — almost half the population — are eligible to be vaccinated. But each state makes the final decision about who goes first. The nation’s 21 million health care workers and three million residents of long-term care facilities were the first to qualify. In mid-January, federal officials urged all states to open up eligibility to everyone 65 and older and to adults of any age with medical conditions that put them at high risk of becoming seriously ill or dying from Covid-19. Adults in the general population are at the back of the line. If federal and state health officials can clear up bottlenecks in vaccine distribution, everyone 16 and older will become eligible as early as this spring or early summer. The vaccine hasn’t been approved in children, although studies are underway. It may be months before a vaccine is available for anyone under the age of 16. Go to your state health website for up-to-date information on vaccination policies in your area

You should not have to pay anything out of pocket to get the vaccine, although you will be asked for insurance information. If you don’t have insurance, you should still be given the vaccine at no charge. Congress passed legislation this spring that bars insurers from applying any cost sharing, such as a co-payment or deductible. It layered on additional protections barring pharmacies, doctors and hospitals from billing patients, including those who are uninsured. Even so, health experts do worry that patients might stumble into loopholes that leave them vulnerable to surprise bills. This could happen to those who are charged a doctor visit fee along with their vaccine, or Americans who have certain types of health coverage that do not fall under the new rules. If you get your vaccine from a doctor’s office or urgent care clinic, talk to them about potential hidden charges. To be sure you won’t get a surprise bill, the best bet is to get your vaccine at a health department vaccination site or a local pharmacy once the shots become more widely available.

Probably not. The answer depends on a number of factors, including the supply in your area at the time you’re vaccinated. Check your state health department website for more information about the vaccines available in your state. The Pfizer and Moderna vaccines are the only two vaccines currently approved, although a third vaccine from Johnson & Johnson is on the way.

That is to be determined. It’s possible that Covid-19 vaccinations will become an annual event, just like the flu shot. Or it may be that the benefits of the vaccine last longer than a year. We have to wait to see how durable the protection from the vaccines is. To determine this, researchers are going to be tracking vaccinated people to look for “breakthrough cases” — those people who get sick with Covid-19 despite vaccination. That is a sign of weakening protection and will give researchers clues about how long the vaccine lasts. They will also be monitoring levels of antibodies and T cells in the blood of vaccinated people to determine whether and when a booster shot might be needed. It’s conceivable that people may need boosters every few months, once a year or only every few years. It’s just a matter of waiting for the data.

Employers do have the right to compel their workers to be vaccinated once a vaccine is formally approved. Many hospital systems, for example, require annual flu shots. But employees can seek exemptions based on medical reasons or religious beliefs. In such cases, employers are supposed to provide a “reasonable accommodation” — with a coronavirus vaccine, for example, a worker might be allowed to work if they wear a mask, or to work from home.

If you have other questions about the coronavirus vaccine, please read our full F.A.Q.

Dr. Pablo J. Sánchez, a committee member from the Research Institute at Nationwide Children’s Hospital in Columbus, Ohio, noted that he has heard from people who had a response to the vaccine that was worse than their previous experience with Covid-19. He suggested that a question about prior infection be added to the information that the C.D.C. requests from vaccine recipients. “It’s not asked,” Dr. Sánchez said. “I do think that is really important.”

Dr. Tom Shimabukuro of the C.D.C., who presented safety data to the committee, said that the agency was investigating the issue. “There’s limited data on that right now but we are looking at ways to which we can get better information,” he said.

People who have had Covid seem to be “reacting to the first dose as if it was a second dose,” said Akiko Iwasaki, an immunologist at the Yale School of Medicine. So one dose is probably “more than enough,” she said.

A study published earlier this month reported that surviving a natural infection provided 83 percent protection from getting infected again over the course of five months. “Giving two doses on top of that appears to be maybe overkill,” she added.

Shane Crotty, an immunologist at the La Jolla Institute for Immunology, pointed out that a more intense vaccine response typically means better protection. If someone had a big response to the first dose, “I would expect that skipping that second dose would be wise and also that the second dose probably is unnecessary,” he said.

But other immunologists suggest everyone stick to two doses. “I’m a big proponent of the right dosing and right schedule, because that’s how the studies were performed,” said Maria Elena Bottazzi, an immunologist at Baylor College of Medicine in Houston.

And getting two shots doesn’t seem to pose any danger to those who have had Covid.

Still, Dr. Malinowski, the ophthalmologist, wishes there were fewer questions and more answers. If vaccine side effects really are more intense in people who have already been infected, health officials could give people a heads up, she said.

“It would be nice to know that, Hey, you might not be able to get out of bed for two days,” Malinowski said. She has decided not to return for a second dose.

Dr. Romano of Mount Sinai Hospital is due for her second shot in February, and isn’t sure what she will do. “My friends who are immunologists, we’ve all sort of been discussing this among ourselves,” she said. “Chances are I’ll probably get it. But I want to think about it a little bit more before I do.”

Denise Grady and Apoorva Mandavilli contributed reporting.

Have You Had Covid-19? Study Says You May Need Only One Vaccine Dose

Had Covid? You May Need Only One Dose of Vaccine, Study Suggests

People who have already been sick with Covid-19 should still be vaccinated, experts say, but they may experience intense side effects even after one dose.

People who received Moderna’s Covid-19 vaccine sat in a waiting area at a vaccination site in San Diego, Calif. 
People who received Moderna’s Covid-19 vaccine sat in a waiting area at a vaccination site in San Diego, Calif. Credit…Ariana Drehsler for The New York Times

  • Feb. 1, 2021, 2:18 p.m. ET

Shannon Romano, a molecular biologist, came down with Covid late last March, about a week after she and her colleagues shut down their lab at Mount Sinai Hospital. A debilitating headache came first, followed by a fever that kept rising, and then excruciating body aches. “I couldn’t sleep. I couldn’t move,” she said. “Every one of my joints just hurt inside.”

It was not an experience she wanted to repeat — ever. So when she became eligible for the Covid-19 vaccine earlier this month, she got the shot.

Two days after her injection, she developed symptoms that felt very familiar. “The way my head hurt and the way my body ached was the same headache and body ache I had when I had Covid,” she said. She recovered quickly, but her body’s intense response to the jab caught her by surprise.

A new study may explain why Dr. Romano and many others who have had Covid report these unexpectedly intense reactions to the first shot of a vaccine. In a study posted online on Monday, researchers found that people who had previously been infected with the virus reported fatigue, headache, chills, fever, and muscle and joint pain after the first shot compared more frequently than did those who had never been infected. Covid survivors also had far higher antibody levels after both the first and second doses of the vaccine.

Based on these results, the researchers say, people who have had Covid-19 may need only one shot.

“I think one vaccination should be sufficient,” said Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai and an author on the study. “This would also spare individuals from unnecessary pain when getting the second dose and it would free up additional vaccine doses.”

While some scientists agree with his logic, others are more cautious. E. John Wherry, director of the University of Pennsylvania’s Institute for Immunology, said that before pushing for a change in policy, he would like to see data showing that those antibodies were able to stop the virus from replicating. “Just because an antibody binds to a part of the virus does not mean it’s going to protect you from being infected,” he said.

It might also be difficult to identify which people have previously been infected, he said. “Documenting that becomes a really potentially messy public health issue,” he said.

A dose of Pfizer’s vaccine was prepared at a vaccination site in Rohnert Park, Calif.
A dose of Pfizer’s vaccine was prepared at a vaccination site in Rohnert Park, Calif.Credit…Jim Wilson/The New York Times

Side effects after vaccination are entirely expected. They show that the immune system is mounting a response and will be better prepared to fight off an infection if the body comes into contact with the virus. The Pfizer and Moderna vaccines are particularly good at evoking a strong response. Most participants in the companies’ trials reported pain at the injection site, and more than half reported fatigue and headaches.

The clinical trials of the authorized vaccines from Pfizer and Moderna, which included more than 30,000 participants each, suggest that most people experience the worst side effects after the second jab. And in the Moderna study, people who had previously been infected actually had fewer side effects than those who hadn’t.

But anecdotally, researchers are hearing from a growing number of people like Dr. Romano who felt ill after one shot. “They describe these symptoms much more vigorously,” Dr. Wherry said.

That matches what Dr. Krammer and his colleagues found in their new study, which has not yet been published in a scientific journal. The researchers assessed symptoms after vaccination in 231 people, of whom 83 had previously been infected, and 148 had not. Both groups widely reported experiencing pain at the injection site after the first dose. But those who had been infected before more often reported fatigue, headache and chills.

The team also looked at how the immune system responded to the vaccine in 109 people — 68 of whom had not previously been infected and 41 who had — and found a more robust antibody response in the latter group. The numbers, however, are small, and so the study’s conclusions will need to be further investigated with more research, experts said.

It’s not necessarily surprising that previously infected individuals might experience more intense reactions. Both shots contain bits of genetic material that spur the body to manufacture spike proteins, the knobby protrusions on the coronavirus’s surface. People who have already been infected with the virus have immune cells that are primed to recognize these proteins. So when the proteins show up after vaccination, some of those immune cells go on the attack, causing people to feel sick.

Dr. Susan Malinowski, an ophthalmologist in Michigan who had Covid-19 in March, certainly felt like her body was under attack after she received the Moderna vaccine. She got the first shot before lunch on New Year’s Eve. By dinner, she was starting to feel ill. She spent the next two days miserable in bed.

“I had fevers. I had chills. I had night sweats. I had pain everywhere in my body,” she said. “I was actually more ill after the vaccine than I was with Covid.”

The entrance to a vaccination site in San Diego. Credit…Ariana Drehsler for The New York Times

Questions about more severe vaccine reactions in people who have already had Covid came up at a Jan. 27 meeting of an expert committee that advises the Centers for Disease Control and Prevention.


Covid-19 Vaccines ›


Answers to Your Vaccine Questions

Currently more than 150 million people — almost half the population — are eligible to be vaccinated. But each state makes the final decision about who goes first. The nation’s 21 million health care workers and three million residents of long-term care facilities were the first to qualify. In mid-January, federal officials urged all states to open up eligibility to everyone 65 and older and to adults of any age with medical conditions that put them at high risk of becoming seriously ill or dying from Covid-19. Adults in the general population are at the back of the line. If federal and state health officials can clear up bottlenecks in vaccine distribution, everyone 16 and older will become eligible as early as this spring or early summer. The vaccine hasn’t been approved in children, although studies are underway. It may be months before a vaccine is available for anyone under the age of 16. Go to your state health website for up-to-date information on vaccination policies in your area

You should not have to pay anything out of pocket to get the vaccine, although you will be asked for insurance information. If you don’t have insurance, you should still be given the vaccine at no charge. Congress passed legislation this spring that bars insurers from applying any cost sharing, such as a co-payment or deductible. It layered on additional protections barring pharmacies, doctors and hospitals from billing patients, including those who are uninsured. Even so, health experts do worry that patients might stumble into loopholes that leave them vulnerable to surprise bills. This could happen to those who are charged a doctor visit fee along with their vaccine, or Americans who have certain types of health coverage that do not fall under the new rules. If you get your vaccine from a doctor’s office or urgent care clinic, talk to them about potential hidden charges. To be sure you won’t get a surprise bill, the best bet is to get your vaccine at a health department vaccination site or a local pharmacy once the shots become more widely available.

Probably not. The answer depends on a number of factors, including the supply in your area at the time you’re vaccinated. Check your state health department website for more information about the vaccines available in your state. The Pfizer and Moderna vaccines are the only two vaccines currently approved, although a third vaccine from Johnson & Johnson is on the way.

That is to be determined. It’s possible that Covid-19 vaccinations will become an annual event, just like the flu shot. Or it may be that the benefits of the vaccine last longer than a year. We have to wait to see how durable the protection from the vaccines is. To determine this, researchers are going to be tracking vaccinated people to look for “breakthrough cases” — those people who get sick with Covid-19 despite vaccination. That is a sign of weakening protection and will give researchers clues about how long the vaccine lasts. They will also be monitoring levels of antibodies and T cells in the blood of vaccinated people to determine whether and when a booster shot might be needed. It’s conceivable that people may need boosters every few months, once a year or only every few years. It’s just a matter of waiting for the data.

Employers do have the right to compel their workers to be vaccinated once a vaccine is formally approved. Many hospital systems, for example, require annual flu shots. But employees can seek exemptions based on medical reasons or religious beliefs. In such cases, employers are supposed to provide a “reasonable accommodation” — with a coronavirus vaccine, for example, a worker might be allowed to work if they wear a mask, or to work from home.

If you have other questions about the coronavirus vaccine, please read our full F.A.Q.

Dr. Pablo J. Sánchez, a committee member from the Research Institute at Nationwide Children’s Hospital in Columbus, Ohio, noted that he has heard from people who had a response to the vaccine that was worse than their previous experience with Covid-19. He suggested that a question about prior infection be added to the information that the C.D.C. requests from vaccine recipients. “It’s not asked,” Dr. Sánchez said. “I do think that is really important.”

Dr. Tom Shimabukuro of the C.D.C., who presented safety data to the committee, said that the agency was investigating the issue. “There’s limited data on that right now but we are looking at ways to which we can get better information,” he said.

People who have had Covid seem to be “reacting to the first dose as if it was a second dose,” said Akiko Iwasaki, an immunologist at the Yale School of Medicine. So one dose is probably “more than enough,” she said.

A study published earlier this month reported that surviving a natural infection provided 83 percent protection from getting infected again over the course of five months. “Giving two doses on top of that appears to be maybe overkill,” she added.

Shane Crotty, an immunologist at the La Jolla Institute for Immunology, pointed out that a more intense vaccine response typically means better protection. If someone had a big response to the first dose, “I would expect that skipping that second dose would be wise and also that the second dose probably is unnecessary,” he said.

But other immunologists suggest everyone stick to two doses. “I’m a big proponent of the right dosing and right schedule, because that’s how the studies were performed,” said Maria Elena Bottazzi, an immunologist at Baylor College of Medicine in Houston.

And getting two shots doesn’t seem to pose any danger to those who have had Covid.

Still, Dr. Malinowski, the ophthalmologist, wishes there were fewer questions and more answers. If vaccine side effects really are more intense in people who have already been infected, health officials could give people a heads up, she said.

“It would be nice to know that, Hey, you might not be able to get out of bed for two days,” Malinowski said. She has decided not to return for a second dose.

Dr. Romano of Mount Sinai Hospital is due for her second shot in February, and isn’t sure what she will do. “My friends who are immunologists, we’ve all sort of been discussing this among ourselves,” she said. “Chances are I’ll probably get it. But I want to think about it a little bit more before I do.”

Denise Grady and Apoorva Mandavilli contributed reporting.

How the Coronavirus Turns the Body Against Itself

How the Coronavirus Turns the Body Against Itself

Some patients struggling with Covid-19 develop antibodies against their own tissues, scientists have found.

A Covid-19 patient at Sharp Grossmont Hospital in La Mesa, Calif., this month. Some patients produce antibodies similar to those produced in more familiar diseases, like lupus. 
A Covid-19 patient at Sharp Grossmont Hospital in La Mesa, Calif., this month. Some patients produce antibodies similar to those produced in more familiar diseases, like lupus. Credit…Etienne Laurent/EPA, via Shutterstock
Apoorva Mandavilli

  • Jan. 28, 2021, 5:00 a.m. ET

The coronavirus can warp the body’s defenses in many ways — disarming the body’s early warning systems, for example, or causing immune cells to misfire. But a spate of new studies suggests another insidious consequence: The infection can trigger the production of antibodies that mistakenly attack the patient’s own tissues instead of the virus.

The latest report, published online this week, suggests that so-called autoantibodies can persist months after the infection has resolved, perhaps causing irreparable harm. If other studies confirm the finding, it may explain some of the lingering symptoms in people who have recovered from Covid-19. The syndrome, sometimes referred to as long Covid, can include dementia, “brain fog” and joint pain.

Autoantibodies are not new to science: They are the misguided soldiers of the immune system, tied to debilitating diseases such as lupus and rheumatoid arthritis, which arise when the body attacks its own tissues.

The newest study is small, with just nine patients, five of whom had autoantibodies for at least seven months. It has not yet undergone peer review for publication, and the authors urged caution in interpreting the results.

“It’s a signal; it is not definitive,” said Dr. Nahid Bhadelia, medical director of the special pathogens unit at Boston Medical Center, who led the study. “We don’t know how prevalent it is, and whether or not it can be linked to long Covid.”

The question of autoimmunity following coronavirus infection is urgent and important, Dr. Bhadelia added. As many as one in three survivors of Covid-19 say they still experience symptoms.

“This is a real phenomenon,” she said. “We’re looking at a second pandemic of people with ongoing potential disability who may not be able to return to work, and that’s a huge impact on the health systems.”

A growing body of evidence suggests that autoimmunity contributes to the severity of Covid-19 in some people. A study published online in October found that among 52 patients with severe Covid-19, more than 70 percent carried antibodies against their own DNA and against proteins that help with blood clotting.

In another study, also published online in October, researchers discovered autoantibodies to carbohydrates made by the body in Covid-19 patients, which could explain neurological symptoms. And a study in the journal Science Translational Medicine in November found that half of patients hospitalized for Covid-19 had at least transient autoantibodies that cause clots and blockages in blood vessels.

The gathering research raises the worrying possibility that lingering autoantibodies might lead to autoimmune disease in some people infected with the coronavirus.

“Once these autoantibodies are induced, there is no going back,” said Akiko Iwasaki, an immunologist at Yale University. “They will be a permanent part of the person’s immune system.”

She added: “What does it do to vaccine response? What does it do to newly acquired infections? These are all questions that will have to be addressed.”

Dr. Iwasaki’s team showed in December that severely ill patients had dramatic increases in a wide array of autoantibodies that target parts of the immune system, brain cells, connective tissue and clotting factors.

“We really see broadly reactive autoantibody responses in these patients,” Dr. Iwasaki said. She had suspected that autoimmunity might play some role, but “even I didn’t expect to see this much auto-reactivity.”

A colorized scanning electron micrograph of a cell (blue) heavily infected with coronavirus particles, isolated from a patient sample in December.
A colorized scanning electron micrograph of a cell (blue) heavily infected with coronavirus particles, isolated from a patient sample in December.Credit…NIAID/National Institutes of Health, via EPA, Shutterstock

Dr. Iwasaki and her colleagues collected blood from 172 patients with a range of symptoms, 22 health care workers who had been infected, and 30 uninfected health care workers.

One in five infected patients had autoantibodies to five proteins in their own bodies, and up to 80 percent to at least one protein, the researchers found. Patients with severe Covid-19 had many more of these antibodies, which hindered their immune responses and exacerbated illness. Of 15 patients who died during the study, 14 had autoantibodies to at least one constituent of the immune system.

The study convincingly shows that autoantibodies “alter the course of disease,” said Marion Pepper, an immunologist at the University of Washington in Seattle who was not involved in the research.

Autoimmunity after an illness is not unique to the coronavirus. Other intensely inflammatory infections, including malaria, leprosy and respiratory viruses, are also known to trigger autoantibodies. But autoimmunity and Covid-19 may be a particularly hazardous mix, experts said.

One analysis of nearly 170,000 people with rare autoimmune rheumatic diseases like lupus and scleroderma indicated that they face increased odds of death from Covid-19. And a study of more than 130,000 people found that autoimmune conditions like Type 1 diabetes, psoriasis and rheumatoid arthritis increase the risk of respiratory complications and death from Covid-19.

Some of the antibodies seemed to be the result of inborn defects in the immune system. For example, a study in the journal Science in October found that about 10 percent of severely ill Covid-19 patients had existing autoantibodies that attacked key components of the immune system that were supposed to kick in after exposure to the virus. Without that rapid response, the body’s defense is hopelessly delayed, fighting a losing battle against the multiplying virus.

Yet the mere presence of autoantibodies does not indicate harm. They are in the general population and don’t always lead to illness, some experts noted.

“Anywhere from 10 to 15 percent of the population has some level of this auto-reactivity,” said Dr. Iñaki Sanz, an immunologist at Emory University. “The issue is that you need many other events downstream of the autoantibodies to induce disease.”

At least in some patients, autoantibodies clearly emerged as a result of the illness, Dr. Iwasaki’s study showed. Extreme inflammation caused by viral infections can cause cells to burst open, spewing their contents and befuddling the immune system’s ability to distinguish “self” from “other.”

But autoantibodies induced in this manner may level off after a few months, said Dr. Shiv Pillai, an immunologist at Harvard University: “Probably in the vast majority of Covid-19 patients, autoantibodies emerge in the acute phase, then decline.”

“That being said — yes, it would be interesting if long Covid might be explained by specific autoantibodies,” he added.

Several researchers, including Dr. Bhadelia and Dr. Iwasaki, are following patients over time to see how long autoantibodies persist and whether they wreak permanent damage. Although scientists have known that acute infections can trigger their presence, the phenomenon has never been studied in such detail.

“That’s maybe the one silver lining here,” Dr. Pepper said. “We’re going to learn some fundamental principles about acute viral infections in people which haven’t been easy to study in this way before.”

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.”

Why Are We So Afraid of Fevers?

Personal Health

Why Are We So Afraid of Fevers?

Under most circumstances, fever is beneficial, reducing the severity of illness and shortening its length.

Credit…Gracia Lam
Jane E. Brody

  • Jan. 11, 2021, 5:00 a.m. ET

Among the many measures my local Y is using to prevent the spread of Covid-19, instant temperatures are taken with a forehead scanner before people can enter the building. Curious to know how “hot” I was one cold, rainy day, I asked the attendant what it registered: 96.2.

The last time my temperature was checked in a medical setting it was 97.5. Whatever happened to 98.6, the degrees Fahrenheit that I and most doctors have long considered normal body temperature?

As if reading my mind, Dr. Philippa Gordon, a Brooklyn pediatrician, sent me an article, “People’s Bodies Now Run Cooler Than ‘Normal’ — Even in the Bolivian Amazon,” by two anthropologists, Michael Gurven and Thomas Kraft, at the University of California, Santa Barbara.

As they wrote in The Conversation, “There is no single universal ‘normal’ body temperature for everyone at all times.” Rather, body temperature varies, not only from one person to another, but also over the course of the day — lower in the morning, higher in the evening; rising during and after exercise; varying at different times in the menstrual cycle, and at different ages — lower for old-timers like me. Aha!

Furthermore, researchers who took hundreds of thousands of temperature readings from people in Palo Alto, Calif., found that 97.5 was the new normal, down about a degree from what the German physician Dr. Carl Wunderlich established in 1867 in a study of 25,000 people. (Dr. Wunderlich’s research did find that “normal” body temperature ranged from 97.2 to 99.5.)

In reviewing data from 1862 through 2017, Dr. Julie Parsonnet, a professor of medicine at Stanford University School of Medicine, and co-authors found a steady decline in average body temperature of about 0.05 degrees Fahrenheit per decade. She has observed that at least 75 percent of normal temperatures are now below 98.6.

If my body temperature registered 98.6, would that mean I have a fever? Possibly, said Sharon S. Evans, a professor of oncology and immunology at Roswell Park Comprehensive Cancer Center in Buffalo, N.Y., even though 100.4 is generally considered the lower end of the fever spectrum.

In a review written with two colleagues, Elizabeth A. Repasky and Daniel T. Fisher, Dr. Evans showed that under most circumstances, fever is beneficial, reducing the severity of illness and shortening its length. (She emphasized, however, that patients should follow their doctors’ advice about taking medications to reduce fever.)

“Fever acts to mobilize multiple arms on the immune system, a function that is remarkably well conserved across many, many species — both warm-blooded and coldblooded,” she explained in an interview. “Fever affects every aspect of the immune system to make it work better.”

For starters, Dr. Evans said, fever activates innate immunity — the mobilization of white blood cells: neutrophils that patrol the body for pathogens and macrophages that gobble them up. Macrophages, in turn, send out an alarm that help is needed, prompting adaptive immunity — T cells and B cells — into action. These cells initiate a specific response to the invader: the production of antibodies days later.

“Treating fever can prolong or worsen illness,” Dr. Paul Offit, vaccinologist at the University of Pennsylvania, stated in “Hippocrates Was Right: Treating Fever Is a Bad Idea,” a fascinating YouTube presentation by the College of Physicians of Philadelphia.

“Fever enhances survival,” Dr. Offit reported. That accounts for its persistence throughout animal evolution, even though it exacts a significant metabolic cost. Immunity, both innate and adaptive, “works better at higher temperatures,” he said.

Thus, when you take medication like acetaminophen (Tylenol and its generic forms) or ibuprofen to suppress a fever, you actually work against the inherent protective benefits nature bestowed. Yes, a fever reducer would likely make you feel better, relieving symptoms like headache, muscle aches and fatigue. But, Dr. Offit emphasized, “You’re not supposed to feel better. You’re supposed to stay under the covers, keep warm and ride out the infection,” not go out and spread it to others.

“We have fevers for a reason,” he said. Fever helps to reduce viral shedding and shorten the length of illnesses like the flu.

Grandma’s proverbial common cold remedy of hot chicken soup likely helps because the steam raises the temperature of nasal passages, repressing reproduction of the virus, he suggested.

Dr. Evans and colleagues wrote, “The fact that fever has been retained throughout vertebrate evolution strongly argues that febrile temperatures confer a survival advantage.” This is true for invertebrates like insects as well. And when coldblooded animals like lizards or bees get sick, they try to raise their body temperature by increasing physical activity or seeking a warmer environment, Dr. Evans said.

So why are we so hellbent on suppressing fevers? Fear is one reason, said Dr. Gordon, the Brooklyn pediatrician, who said frantic parents often call in the middle of the night when a child’s fever spikes. She suggested that doctors warn parents ahead of time to expect a nighttime rise in a child’s fever and explain that high fevers from an infection are not damaging.

“The body has a built-in thermostat — the hypothalamus — that keeps temperatures from getting high enough to cause damage,” she said, and febrile seizures (brief convulsions, shaking and perhaps loss of consciousness that affect some young children) result from how fast temperatures rise, not how high they get. In a genetically susceptible child, a seizure can occur when the temperature rises quickly even at low temperatures, say, from 99 to 100.8.

“Febrile seizures are creepy and terrifying for parents to watch, but they don’t cause any damage,” Dr. Gordon said. She added, however, that fever is worrisome in very young babies who have immature immune systems and haven’t yet been vaccinated against serious diseases.

Even knowing the infection-fighting benefits of fever, Dr. Gordon said she would still recommend medication to lower a fever if a child, especially a nonverbal child, is very miserable and perhaps unable to sleep or eat.

Adults are generally advised to seek medical help if their fever rises above 103 degrees.

An important caveat about high fevers: Unlike fevers resulting from an infection, there is no natural shut-off for environmentally induced fevers, such as might occur if a child is shut in a hot car or an overdressed athlete overexercises on a hot day, which can result in fatal heat stroke.

Consumers should also consider how a temperature is taken before interpreting the results. An ear temperature is usually slightly higher than an oral temperature, which in turn is higher than an armpit temperature or a forehead scan.

To assure a reliable reading, the temperature of newborns should be taken with a rectal thermometer, Dr. Gordon said. But for older children with a fever, the exact number of degrees doesn’t really matter unless they’ve not been immunized, she said.

The Covid Balancing Act for Doctors

Doctors

The Covid Balancing Act

At the start of the pandemic, I was “Dr. No” to my in-laws and cancer patients, but my conversations have become more nuanced.

Credit…Getty Images

  • Jan. 7, 2021, 5:00 a.m. ET

My wife’s parents have led a relatively monastic existence since about mid-March.

Both are in their 80s and live independently in rural Pennsylvania, maintaining a three-acre property by themselves. My father-in-law, the older of the two, has skirted major medical problems despite a decades-long indiscriminate diet, a testimony to the triumph of genetics over lifestyle choices. My mother-in-law, on the other hand, has been ravaged by lupus, which flares regularly and requires medications that suppress her immune system.

So when Covid-19 hit, we feared for their health, given their ages and her compromised immunity, and begged that they place themselves on lockdown, so we wouldn’t lose them to the pandemic.

And they did.

Where they used to buy groceries at their local Giant Eagle supermarket (which they call the “Big Bird,”) they turned instead to Instacart for home delivery, shrugging off the random items their shopper would get wrong with good humor.

Where they used to attend church in person every Sunday, they caught the video highlights online when they became available on Monday morning.

We arranged weekly Zoom calls with them, to replace our frequent visits.

We used to say that their social life rivaled ours, as they got together with friends they have known since kindergarten (kindergarten!) several times each week for dinner, drinks or shows. Instead, during the pandemic, they’ve replaced those social events with going cruising together in their blue ’55 Chevy Bel Air, satisfying themselves with the feel of a car they first drove in their teens, the beautiful countryside and a wave at their friends, who sat at a safe distance on their front porches.

Our whole family has been proud of them to the point of bursting. But in September, after six months of this, my father-in-law got antsy and did the unthinkable: He went to the hardware store, ostensibly for a tool, but really to see his friends who tend to congregate there.

He caught hell for his modest indiscretion, first from his wife, and then from mine. They explained to him that he could have ordered the piece online. They reminded him that his actions can affect my mother-in-law, and her frail health, too. Finally, he had enough.

“I’m 85 years old,” he said. “Eighty-five! I’m careful, I wore a mask. What do you expect me to do, spend the rest of my days here in prison?”

That gave me pause — my wife, too. At 85, he had done the math. Despite his lucky genetics, he probably didn’t have many years left on this earth, and he didn’t want to spend one or two of them in isolation.

Understanding the risks and consequences of his actions, shouldn’t he be allowed to see his buddies at the hardware store, and maybe buy a tool while he’s there?

I thought about it from the perspective of my patients, many of whom also don’t have much time left on this earth, and the conversations we had been having in clinic.

At the beginning of the pandemic, I was “Dr. No,” prohibiting my patients, most of whom have devastated immune systems, from engaging in their usual social activities. Where much of what we had all been hearing from government authorities about Covid-19 transmission had often been contradictory, I wanted to give concrete advice.

Attending a family gathering to celebrate a birthday? No.

How about a high school graduation party for a granddaughter? No.

Visiting elderly parents in another state? Not safe for you or them.

A road trip to Montana with a friend (this from a man in his 80s with leukemia): Are you kidding me?

At the risk of sounding paternalistic, I feared for my patients’ health, as I did for my in-laws’ health, and wanted to protect them.

But perhaps because our understanding of Covid-19’s epidemiology has gotten better over time; or with our recognition that we may have to live with the pandemic for many months more; or given my father-in-law’s perspective that people at the end of life should make their own risk-benefit calculations, my conversations have now become more nuanced.

I’m more open to my patients not missing important life events, when there may not be much life for them left, provided they take precautions to avoid endangering themselves or those around them, particularly amid the most recent surge in Covid-19 cases.

One woman with leukemia was receiving chemotherapy early in 2020 when her daughter had a miscarriage. Now that her daughter is eight months pregnant again, can she hold the baby when it is born? Absolutely, let’s talk about how to do it safely.

Another patient’s mother died. Can she attend the funeral? Yes, with appropriate distancing, limited numbers, and personal protective equipment. But skip the reception.

The road trip to Montana? I still wasn’t comfortable with that, but my patient and his friend went anyway, took their own food, slept in their truck, and he returned without Covid-19.

And my father-in-law? He gets out of the house a little bit more than he used to, but not as much as he’d like. The rare times that he does nowadays, he is always masked and stays outdoors, and both he and my mother-in-law remain Covid-19-free.

Which strikes me as about the right balance.

Mikkael Sekeres (@mikkaelsekeres) is the chief of the Division of Hematology, Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine and author of When Blood Breaks Down: Life Lessons from Leukemia.”

Small Number of Covid Patients Develop Severe Psychotic Symptoms

Small Number of Covid Patients Develop Severe Psychotic Symptoms

Most had no history of mental illness and became psychotic weeks after contracting the virus. Cases are expected to remain rare but are being reported worldwide.

Dr. Hisam Goueli treated several psychotic patients who had never had mental health issues before, including a woman who told him she kept visualizing her children being murdered. “It was like she was experiencing a movie,” he said.
Dr. Hisam Goueli treated several psychotic patients who had never had mental health issues before, including a woman who told him she kept visualizing her children being murdered. “It was like she was experiencing a movie,” he said.Credit…Jovelle Tamayo for The New York Times
Pam Belluck

  • Dec. 28, 2020, 12:03 p.m. ET

Almost immediately, Dr. Hisam Goueli could tell that the patient who came to his psychiatric hospital on Long Island this summer was unusual.

The patient, a 42-year-old physical therapist and mother of four young children, had never had psychiatric symptoms or any family history of mental illness. Yet there she was, sitting at a table in a beige-walled room at South Oaks Hospital in Amityville, N.Y., sobbing and saying that she kept seeing her children, ages 2 to 10, being gruesomely murdered and that she herself had crafted plans to kill them.

“It was like she was experiencing a movie, like ‘Kill Bill,’” Dr. Goueli, a psychiatrist, said.

The patient described one of her children being run over by a truck and another decapitated. “It’s a horrifying thing that here’s this well-accomplished woman and she’s like ‘I love my kids, and I don’t know why I feel this way that I want to decapitate them,’” he said.

The only notable thing about her medical history was that the woman, who declined to be interviewed but allowed Dr. Goueli to describe her case, had become infected with the coronavirus in the spring. She had experienced only mild physical symptoms from the virus, but, months later, she heard a voice that first told her to kill herself and then told her to kill her children.

At South Oaks, which has an inpatient psychiatric treatment program for Covid-19 patients, Dr. Goueli was unsure whether the coronavirus was connected to the woman’s psychological symptoms. “Maybe this is Covid-related, maybe it’s not,” he recalled thinking.

“But then,” he said, “we saw a second case, a third case and a fourth case, and we’re like ‘There’s something happening.’”

Indeed, doctors are reporting similar cases across the country and around the world. A small number of Covid patients who had never experienced mental health problems are developing severe psychotic symptoms weeks after contracting the coronavirus.

In interviews and scientific articles, doctors described:

A 36-year-old nursing home employee in North Carolina who became so paranoid that she believed her three children would be kidnapped and, to save them, tried to pass them through a fast-food restaurant’s drive-through window.

A 30-year-old construction worker in New York City who became so delusional that he imagined his cousin was going to murder him, and, to protect himself, he tried to strangle his cousin in bed.

A 55-year-old woman in Britain had hallucinations of monkeys and a lion and became convinced a family member had been replaced by an impostor.

Beyond individual reports, a British study of neurological or psychiatric complications in 153 patients hospitalized with Covid-19 found that 10 people had “new-onset psychosis.” Another study identified 10 such patients in one hospital in Spain. And in Covid-related social media groups, medical professionals discuss seeing patients with similar symptoms in the Midwest, Great Plains and elsewhere.

“My guess is any place that is seeing Covid is probably seeing this,” said Dr. Colin Smith at Duke University Medical Center in Durham, who helped treat the North Carolina woman. He and other doctors said their patients were too fragile to be asked whether they wanted to be interviewed for this article, but some, including the North Carolina woman, agreed to have their cases described in scientific papers.

Medical experts say they expect that such extreme psychiatric dysfunction will affect only a small proportion of patients. But the cases are considered examples of another way the Covid-19 disease process can affect mental health and brain function.

Although the coronavirus was initially thought primarily to cause respiratory distress, there is now ample evidence of many other symptoms, including neurological, cognitive and psychological effects, that could emerge even in patients who didn’t develop serious lung, heart or circulatory problems. Such symptoms can be just as debilitating to a person’s ability to function and work, and it’s often unclear how long they will last or how to treat them.

Experts increasingly believe brain-related effects may be linked to the body’s immune system response to the coronavirus and possibly to vascular problems or surges of inflammation caused by the disease process.

“Some of the neurotoxins that are reactions to immune activation can go to the brain, through the blood-brain barrier, and can induce this damage,” said Dr. Vilma Gabbay, a co-director of the Psychiatry Research Institute at Montefiore Einstein in the Bronx.

Brain scans, spinal fluid analyses and other tests didn’t find any brain infection, said Dr. Gabbay, whose hospital has treated two patients with post-Covid psychosis: a 49-year-old man who heard voices and believed he was the devil and a 34-year-old woman who began carrying a knife, disrobing in front of strangers and putting hand sanitizer in her food.

Physically, most of these patients didn’t get very sick from Covid-19, reports indicate. The patients that Dr. Goueli treated experienced no respiratory problems, but they did have subtle neurological symptoms like hand tingling, vertigo, headaches or diminished smell. Then, two weeks to several months later, he said, they “develop this profound psychosis, which is really dangerous and scary to all of the people around them.”

Also striking is that most patients have been in their 30s, 40s and 50s. “It’s very rare for you to develop this type of psychosis in this age range,” Dr. Goueli said, since such symptoms more typically accompany schizophrenia in young people or dementia in older patients. And some patients — like the physical therapist who took herself to the hospital — understood something was wrong, while usually “people with psychosis don’t have an insight that they’ve lost touch with reality.”

Some post-Covid patients who developed psychosis needed weeks of hospitalization in which doctors tried different medications before finding one that helped.

Dr. Robert Yolken, a neurovirology expert at Johns Hopkins University School of Medicine in Baltimore, said that although people might recover physically from Covid-19, in some cases their immune systems, might be unable to shut down or might remain engaged because of “delayed clearance of a small amount of virus.”

Persistent immune activation is also a leading explanation for brain fog and memory problems bedeviling many Covid survivors, and Emily Severance, a schizophrenia expert at Johns Hopkins, said post-Covid cognitive and psychiatric effects might result from “something similar happening in the brain.”

It may hinge on which brain region the immune response affects, Dr. Yolken said, adding, “some people have neurological symptoms, some people psychiatric and many people have a combination.”

From left, Drs. Jonathan Komisar, Brian Kincaid and Colin Smith of Duke University Medical Center, who treated a woman whose sudden psychosis made her paranoid that her children were about to be kidnapped and that cellphones were tracking her.
From left, Drs. Jonathan Komisar, Brian Kincaid and Colin Smith of Duke University Medical Center, who treated a woman whose sudden psychosis made her paranoid that her children were about to be kidnapped and that cellphones were tracking her.Credit…Jeremy M. Lange for The New York Times

Experts don’t know whether genetic makeup or perhaps an undetected predisposition for psychiatric illness put some people at greater risk. Dr. Brian Kincaid, medical director of psychiatric emergency department services at Duke, said the North Carolina woman once had a skin reaction to another virus, which might suggest her immune system responds zealously to viral infections.

Sporadic cases of post-infectious psychosis and mania have occurred with other viruses, including the 1918 flu and the coronaviruses SARS and MERS.

“We think that it’s not unique to Covid,” said Dr. Jonathan Alpert, chairman of psychiatry and behavioral sciences at Albert Einstein College of Medicine, who co-wrote the report on the Montefiore patients. He said studying these cases might help to increase doctors’ understanding of psychosis.

The symptoms have ranged widely, some surprisingly severe for a first psychotic episode, experts said. Dr. Goueli said a 46-year-old pharmacy technician, whose family brought her in after she became fearful that evil spirits had invaded her home, “cried literally for four days” in the hospital.

He said the 30-year-old construction worker, brought to the hospital by the police, became “extremely violent,” dismantling a hospital radiator and using its parts and his shoes to try to break out of a window. He also swung a chair at hospital staff.

How long the psychosis lasted and patients’ response to treatment has varied. The woman in Britain — whose symptoms included paranoia about the color red and terror that nurses were devils who would harm her and a family member — took about 40 days to recover, according to a case report.

The 49-year-old man treated at Montefiore was discharged after several weeks’ hospitalization, but “he was still struggling two months out” and required readmission, Dr. Gabbay said.

The North Carolina woman, who was convinced that cellphones were tracking her and that her partner would steal her pandemic stimulus money, didn’t improve with the first medication, said Dr. Jonathan Komisar at Duke, who said doctors initially thought her symptoms reflected bipolar disorder. “When we began to realize that maybe this isn’t going resolve immediately,” he said, she was given an antipsychotic, risperidone and discharged in a week.

The physical therapist who planned to murder her children had more difficulty. “Every day, she was getting worse,” Dr. Goueli said. “We tried probably eight different medicines,” including antidepressants, antipsychotics and lithium. “She was so ill that we were considering electroconvulsive therapy for her because nothing was working.”

About two weeks into her hospitalization, she couldn’t remember what her 2-year-old looked like. Calls with family were heartbreaking because “‘You could hear one in the background saying ‘When is Mom coming home?’” Dr. Goueli said. “That brought her a lot of shame because she was like, ‘I can’t be around my kids and here they are loving me.’”

Ultimately, risperidone proved effective and after four weeks, she returned home to her family, “95 percent perfect,” he said.

“We don’t know what the natural course of this is,” Dr. Goueli said. “Does this eventually go away? Do people get better? How long does that normally take? And are you then more prone to have other psychiatric issues as a result? There are just so many unanswered questions.”

What People With Allergies Should Know About Covid Vaccines

Here’s What People With Allergies Should Know About Covid Vaccines

Four people so far have had allergic reactions after getting the Pfizer-BioNTech vaccine. Experts say that shouldn’t deter most people from getting a jab.

Vaccinations underway in Orange, Calif., on Wednesday.
Vaccinations underway in Orange, Calif., on Wednesday.Credit…Jenna Schoenefeld for The New York Times
Katherine J. Wu

  • Dec. 18, 2020, 12:27 p.m. ET

Allergic reactions reported in two health workers who received a dose of Pfizer’s vaccine in Alaska this week have reignited concerns that people with a history of extreme immune flare-ups might not be good candidates for the newly cleared shots.

The two incidents follow another pair of cases in Britain. Three of the four were severe enough to qualify as anaphylaxis, a severe and potentially life-threatening reaction. But all four people appear to have recovered.

Health officials on both sides of the pond are vigilantly monitoring vaccinated people to see if more cases emerge. Last week, British drug regulators recommended against the use of Pfizer’s vaccine in people who have previously had anaphylactic reactions to food, medicines or vaccines.

And on Thursday, Dr. Doran Fink, deputy director of the Food and Drug Administration’s clinical division of vaccines and related products applications, addressed the issue during a meeting about the vaccine made by Moderna that contains similar ingredients and is expected to soon receive emergency use authorization, or E.U.A., from the agency.

“We anticipate that there may be additional reports, which we will rapidly investigate,” Dr. Fink said, adding that robust surveillance systems were in place to detect these rare events.

Still, Dr. Fink said that “the totality of data at this time continue to support vaccinations under the Pfizer E.U.A., without new restrictions.”

The F.D.A., he added, would work with Pfizer to revise fact sheets and prescribing information for the vaccine so that the public would understand the risk of allergic reactions and know how to report them.

What do we know about the people who had bad reactions?

The first two confirmed cases of allergic reactions came from two health care workers in Britain. Both had a medical history of serious allergic reactions, but had not previously been known to have trouble with any of the vaccine’s ingredients. After an injection of epinephrine — the typical treatment for anaphylaxis — both recovered.

(A third British incident described as a “possible allergic reaction” was also reported and appears to have been minor.)

On Wednesday, two health workers in Alaska experienced reactions as well. One was too mild to be deemed anaphylaxis. But the other, which occurred in a middle-aged woman with no history of allergies, was serious enough to warrant hospitalization, even after she got a shot of epinephrine.

“What is happening does seem really unusual to me,” said Dr. Kimberly Blumenthal, an allergist, immunologist and drug allergy researcher at Massachusetts General Hospital. Vaccine-related allergic reactions are typically rare, occurring at a rate of about one in a million.

Dr. Blumenthal also pointed out that it was a bit bizarre to see allergic reactions clustering in just two locations: Britain and Alaska. Zeroing in on the commonalities between the two hot spots, she said, might help researchers puzzle out the source of the problem.

Do we know for sure that their reactions were caused by the vaccine?

British and U.S. agencies are investigating the causes, but no official has declared a direct link.

But Dr. Blumenthal suspects they were connected to the shots, because the reactions were immediate, occurring within minutes of injection.

“We have to think it was related because of the timing,” she said.

Nor is it known if a particular ingredient might have been the cause. Pfizer’s vaccine contains just 10 ingredients. The most important is a molecule called messenger RNA, or mRNA — genetic material that can instruct human cells to make a coronavirus protein called spike. Once manufactured, spike teaches the immune system to recognize the coronavirus so it can be fought off in the future. Messenger RNA, which is naturally found in human cells, is unlikely to pose a threat, and degrades within about a day of being injected.

The other nine ingredients are a mix of salts, fatty substances and sugars that stabilize the vaccine. None are common allergens. The only chemical with a history of causing allergic reactions is polyethylene glycol, or PEG, which helps package the mRNA into an oily sheath, protecting it as it goes into human cells.

But PEG is, generally speaking, inert and widespread. It’s found in ultrasound gel, laxatives like Miralax and injectable steroids, among other drugs and products, Dr. Blumenthal said. Despite the chemical’s ubiquity, she said, “I’ve only seen one case of a PEG allergy — it’s really, really uncommon.”

It’s still possible that something else could be causing the reactions — perhaps a factor related to how the vaccines are transported, thawed or administered, Dr. Blumenthal said.

Did the volunteers in Pfizer’s clinical trials have any bad reactions?

A small number of volunteers in Pfizer’s clinical trials experienced allergic reactions. Just one of the 18,801 participants who received the vaccine in a late-stage trial had anaphylaxis, and the incident was deemed unrelated to the vaccine, said Steven Danehy, a spokesman for Pfizer. No severe reactions were found in people who got a placebo shot.

Pfizer excluded people with a history of anaphylaxis to vaccines from its clinical trials.

What does the F.D.A. say about these reactions?

Several experts raised concerns about the allergic reactions in meetings convened to discuss both Pfizer’s and Moderna’s vaccines. The agency has advised caution, noting that health care providers should not administer the vaccine to anyone with a “known history of a severe allergic reaction” to any component of the vaccine — a standard warning for vaccines.

Should people with mild allergies wait to get vaccinated?

There’s no evidence that people with mild allergies, which are quite common, need to avoid the vaccine. Allergies are, simply put, the product of an inappropriate immune response against something harmless — pollen, peanuts, cat dander and the like. In many cases, the results of this overreaction are mild symptoms such as a runny nose, coughing or sneezing.

But allergies are specific: A reaction to one substance does not guarantee a reaction to another. On Monday, the American College of Allergy, Asthma and Immunology released guidance stating that people with common allergies “are no more likely than the general public to have an allergic reaction to the Pfizer-BioNTech Covid-19 vaccine.”

William Amarquaye, a clinical pharmacist at Brandon Regional Hospital, said he wouldn’t let his asthma or allergies stop him from taking the vaccine when it is offered to him in the next few weeks. He’s also never had trouble with other vaccines he has taken in the past.

“It should still be OK to take the vaccine,” Dr. Amarquaye said. “I’m actually excited about it.”

What about people with a history of severe allergies?

Most people in this category should be good to go, too, said Dr. Eun-Hyung Lee, an expert in allergy and immunology at Emory University.

Guidelines released by the Centers for Disease Control and Prevention identify only one group of people who might not want to get Pfizer’s vaccine: those with a known history of severe allergic reactions to an ingredient in the injection.

People with a history of anaphylaxis to any other substance, including other vaccines or injectable drugs, can still get the vaccine, but should consult their health care providers and be monitored for 30 minutes after getting their shots. Everyone else, like people with mild or no allergies, need to wait only 15 minutes before leaving the vaccination site.

“In general, the immediate reactions that require epinephrine are those that happen within the first 30 minutes,” said Dr. Merin Kuruvilla, an allergist and immunologist at Emory University.

Some people will understandably be concerned. Dr. Taison Bell, a critical care physician at UVA Health in Charlottesville, Va., said he worried about his 7-year-old son, Alain, who is severely allergic to several foods, including wheat, peanuts and cow’s milk. Alain has about two bouts of anaphylaxis each year.

It’s a bit of a relief that Alain is “later in the prioritization schema,” Dr. Bell said. By the time a vaccine is ready for him, he said, “we’ll get a better sense for how serious this is.” The family plans to discuss their situation with Alain’s doctor.

Ultimately, it’s unlikely that any of the ingredients in a coronavirus vaccine would cause Alain any issues. Alain has tolerated other vaccines, including the flu shot, in previous years, and is looking forward to his own shot at immunization to the coronavirus, said Dr. Bell, who received his first dose of Pfizer’s vaccine on Tuesday.

What about Moderna’s vaccine?

Two volunteers in Moderna’s late-stage clinical trial developed anaphylactic reactions, the company reported at the F.D.A. committee meeting on Thursday. Neither was deemed to be linked to the company’s vaccine, which also contains mRNA, because they occurred weeks or months after the participants received their shots. One of these volunteers also had a history of asthma and a shellfish allergy.

Moderna, unlike Pfizer, did not exclude people with a history of anaphylaxis from its trials.

Dr. Tal Zaks, the company’s chief medical officer, said that while Moderna’s vaccine recipe was similar to Pfizer’s, key molecular differences existed that could set the two products on different paths. He said that bad reactions to Pfizer’s vaccine did not guarantee that similar events would happen in relation to the Moderna shots.

Both vaccines do, however, include a version of PEG.

Dr. Blumenthal and others said that anyone concerned about having an allergic reaction to a vaccine should seek the advice of a health care provider.

For anyone getting the vaccine, it’s all about “balancing out the risks,” Dr. Lee, of Emory, said. Allergic reactions can be dangerous. But they are rare and treatable, and the tools to combat them should be available at all vaccination sites. The coronavirus, on the other hand, can have far graver consequences.

“When it’s my turn in line, I think weighing these odds is what I would do,” Dr. Lee said.

Their Teeth Fell Out. Was It Another Covid-19 Consequence?

Earlier this month, Farah Khemili popped a wintergreen breath mint in her mouth and noticed a strange sensation: a bottom tooth wiggling against her tongue.

Ms. Khemili, 43, of Voorheesville, N.Y., had never lost an adult tooth. She touched the tooth to confirm it was loose, initially thinking the problem might be the mint. The next day, the tooth flew out of her mouth and into her hand. There was neither blood nor pain.

Ms. Khemili survived a bout with Covid-19 this spring, and has joined an online support group as she has endured a slew of symptoms experienced by many other “long haulers”: brain fog, muscle aches and nerve pain.

There’s no rigorous evidence yet that the infection can lead to tooth loss or related problems. But among members of her support group, she found others who also described teeth falling out, as well as sensitive gums and teeth turning gray or chipping.

She and other survivors unnerved by Covid’s well-documented effects on the circulatory system, as well as symptoms such as swollen toes and hair loss, suspect a connection to tooth loss as well. But some dentists, citing a lack of data, are skeptical that Covid-19 alone could cause dental symptoms.

“It’s extremely rare that teeth will literally fall out of their sockets,” said Dr. David Okano, a periodontist at the University of Utah in Salt Lake City.

But existing dental problems may worsen as a result of Covid-19, he added, especially as patients recover from the acute infections and contend with its long-term effects.

And some experts say that doctors and dentists need to be open to such possibilities, especially because more than 47 percent of adults 30 years or older have some form of periodontal disease, including infections and inflammation of the gums and bone that surround teeth, according to a 2012 report from the Centers for Disease Control and Prevention.

“We are now beginning to examine some of the bewildering and sometimes disabling symptoms that patients are suffering months after they’ve recovered from Covid,” including these accounts of dental issues and teeth loss, said Dr. William W. Li, president and medical director of the Angiogenesis Foundation, a nonprofit that studies the health and disease of blood vessels.

While Ms. Khemili had become more diligent about her dental care, she had a history of dental issues before contracting the coronavirus. When she went to the dentist the day after her tooth came out, he found that her gums were not infected but she had significant bone loss from smoking. He referred Ms. Khemili to a specialist to handle a reconstruction. The dental procedure is likely to cost her just shy of $50,000.

The same day Ms. Khemili’s tooth fell out, her partner went on Survivor Corp, a Facebook page for people who have lived through Covid-19. There, he found that Diana Berrent, the page’s founder, was reporting that her 12-year-old son had lost one of his adult teeth, months after he had a mild case of Covid-19. (Unlike Ms. Khemili, Ms. Berrent’s son had normal and healthy teeth with no underlying disease, according to his orthodontist.)

Others in the Facebook group have posted about teeth falling out without bleeding. One woman lost a tooth while eating ice cream. Eileen Luciano of Edison, N.J., had a top molar pop out in early November when she was flossing.

“That was the last thing that I thought would happen, that my teeth would fall out,” Ms. Luciano said.

[Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.]

Teeth falling out without any blood is unusual, Dr. Li said, and provides a clue that there might be something going on with the blood vessels in the gums.

The new coronavirus wreaks havoc by binding to the ACE2 protein, which is ubiquitous in the human body. Not only is it found in the lungs, but also on nerve and endothelial cells. Therefore, Dr. Li says, it’s possible that the virus has damaged the blood vessels that keep the teeth alive in Covid-19 survivors; that also may explain why those who have lost their teeth feel no pain.

It’s also possible that the widespread immune response, known as a cytokine storm, may be manifesting in the mouth.

“If a Covid long hauler’s reaction is in the mouth, it’s a defense mechanism against the virus,” said Dr. Michael Scherer, a prosthodontist in Sonora, Calif. Other inflammatory health conditions, such as cardiovascular disease and diabetes, he said, also correlate with gum disease in the same patients.

“Gum disease is very sensitive to hyper-inflammatory reactions, and Covid long haulers certainly fall into that category,” Dr. Scherer said.

Dentists haven’t seen many of these cases, and some dismiss these individual claims. But physicians like Dr. Li say Covid-19’s surprises require that the profession be on the lookout for unexpected consequences of the disease.

“Patients may be bringing in new findings,” he said, and physicians and dentists need to cooperate on understanding the effects of long-term Covid-19 on teeth.

For now, Ms. Khemili hopes her story may serve as a cautionary tale. If people aren’t taking the proper precautions to protect themselves from the coronavirus, “they could be looking at something like this.”

Think Like a Doctor: The Boy With Nighttime Fevers Solved!

Photo

Credit Andreas Samuelsson

On Thursday we asked Well readers to take on the case of a 7-year-old boy who’d been having fevers and drenching sweats nightly for over a month. More than 300 of you wrote in, and although 20 of you came up with the right diagnosis, only three of you figured out both the diagnosis and the test needed to confirm it.

The correct diagnosis is…

Coccidioidomycosis, or valley fever.

The diagnosis was made based on a lymph node biopsy.

The first reader to suggest this diagnosis and the test was Dr. Malkhaz Jalagonia, an internist from Zugdidi, in the Republic of Georgia. He says he’s never seen a case like this, but he’s fascinated by zebras and so recognized the disease immediately. Well done, Dr. Jalagonia!

One of the reasons I chose this case was that, although this diagnosis is rare in life, it was the most frequently suggested diagnosis in my last column – the one about the middle-aged man with a cough for over a year. I thought it would be fun to show what valley fever really looks like. Hope you did too.

The Diagnosis

Coccidioidomycosis is a lung infection usually caused by inhaling the spores of a tiny fungus called coccidioides. This organism grows as a mold, a few inches below the surface of the soil in deserts in parts of the southwestern United States, Mexico and other countries of Central America.

In dry conditions, the fungus becomes fragile and is easily broken up into tiny single-celled spores that can be sent airborne with even the slightest disturbance. And once these single cells are aloft they can remain suspended there for prolonged periods of time.

Infection is usually acquired by inhaling the spores. Once lodged in the lung, the organism begins to reproduce almost immediately. The time course between exposure and disease depends on the inhaled dose and the patient’s immune system.

Symptoms, or No Symptoms

Disease severity varies considerably. Nearly half of those who breathe in these spores have no symptoms, or symptoms are so mild they never visit the doctor’s office.

More severe infection usually takes the form of a slowly progressive pneumonia known as coccidioidomycosis, or valley fever. This illness is characterized by a cough, fevers, chest pain, fatigue and sometimes joint pain. Indeed, because of the prominent joint pain, in some cases — though not this one — the disease is also known as desert rheumatism.

Rashes are also seen in many patients. Those who get a rash seem to have a more benign course of illness. The thinking is that the skin symptoms are the result of an aggressive immune response in the host to the pathogen.

Symptoms can last for months, and in many cases they resolve without treatment. But in some cases they get worse.

Hard to Diagnose

Those who seek medical attention are often not diagnosed — or not diagnosed quickly — because the symptoms of valley fever are not very specific, and few of the tests that doctors usually order have features that are unusual enough to suggest the diagnosis.

Chest X-rays are often normal. Blood tests may be normal as well, though some patients, like this child, have an unusually high number of a type of white blood cell known as eosinophils. These cells are usually seen in allergic responses or with infections due to parasites.

The most important clue to the possibility of this infection is travel to one of the areas where the fungus lives. In the United States, valley fever is endemic primarily in Arizona and southern California, as well as parts of southern New Mexico and West Texas. Indeed, the name valley fever is a shorter and more general term for an earlier name, San Joaquin Valley fever, because it was so common in that part of California.

A Dramatic Rise

There has been a significant increase in the number of cases of coccidioidomycosis in the past 15 years, with nearly 10 times as many in areas where the fungus is found. Development in areas where the fungus is endemic is thought to be the primary cause. Better diagnostic testing may also play a role.

While this infection may cause only a minor illness in many, there are some – like this child – for whom the disease can spread beyond the lungs into the rest of the body. Disseminated coccidioidomycosis is usually seen in those with some problem with the immune system – an underlying disorder such as H.I.V., for example, or because someone is taking immune suppressing medications such as prednisone.

Once out of the lungs, the bugs can go anywhere in the body, though they seem to prefer joints, skin or bones. Those with disseminated disease have to be treated for a long time – often up to a year, or occasionally for life.

How the Diagnosis Was Made

The little boy had been sick for nearly a month, and his parents were getting quite worried. He was pale, thin and really, really tired.

With their pediatrician’s encouragement, they had gone on a long planned, much anticipated vacation to the mountains of Colorado. But the child wasn’t getting better, and so his mother took him to yet another doctor – this one in a walk-in clinic.

The results of some simple blood tests done at that visit worried the doctor, who suggested that the boy be taken to a hematologist, a specialist in diseases and cancers of the blood.

Now the parents were terrified. The mother faxed copies of the lab results to her brother, a researcher in immunology. He wasn’t a physician but showed the results to friends who were. They agreed with the doctor at the walk-in clinic: The boy needed to be seen by a hematologist.

A Series of Specialists

The next morning the family headed home to Minneapolis. They took the boy to his regular pediatrician, who sent them to a hematologist. It wasn’t cancer, that specialist told them. Maybe some kind of severe food allergy, he suggested, and referred them to a gastroenterologist.

Not a GI thing, that specialist told them, and he referred the now nearly frantic family to an infectious disease specialist and a rheumatologist.

Nearly 10 days after getting the alarming blood test results, the couple and their child found themselves in the office of Dr. Bazak Sharon, a specialist in infectious diseases in adults and children at the University of Minnesota Masonic Children’s Hospital. After introducing himself, Dr. Sharon settled down to get a detailed history of the boy and the family.

A Desert Visit, but Other Possibilities

When Dr. Sharon heard that the family had spent a week at a ranch in the desert of Arizona, he immediately thought of coccidioidomycosis. The fungus isn’t found in Minnesota or Colorado – which is probably why other doctors hadn’t considered it. But it is all over the part of Arizona where they’d visited.

Still, there were other possibilities that had to be ruled out, including some types of cancer. After Dr. Sharon examined the boy, he sent the family to the lab for a chest X-ray and some blood tests.

The results of those tests were concerning. The child was getting worse. Dr. Sharon wasn’t going to be back in clinic for a week, and he was certain the child needed to be seen and diagnosed well before then. He called a friend and colleague who was taking care of patients in the hospital, Dr. Abraham Jacob, and asked if he would admit the child and coordinate the needed diagnostic workup for the boy.

First Some Answers, Then More Questions

Once in the hospital, the child had a chest CT scan. The results were frightening. The lymph nodes that surround the trachea, the tube that carries inspired air to the lungs, were hugely enlarged. They were so big that the trachea was almost completely blocked. The opening at one point was just two millimeters wide – basically the dimensions of a cocktail straw. Any worsening of his disease might cause the tube to close completely, making breathing impossible.

A pediatric surgeon was brought in immediately. The enlarged lymph nodes had to be removed. First in order to protect the child’s airways. And second because those nodes would reveal what the little boy had.

But trying to do surgery on a 7-year-old boy’s neck was complicated. Although the surgeon could easily feel the enlarged gland in his neck, it was close to many vital blood vessels, nerves and organs. The child had to lie perfectly still, and with most children that could only be guaranteed if they were under anesthesia.

Risky Surgery

When the anesthesiologist saw the CT scan, the doctors’ concern grew. They could put the child to sleep, but if anything went wrong during surgery and they had to put a tube down his throat into his lungs, they weren’t sure it would be able to fit.

The trachea was so small, there was no guarantee they could get the tube into place. In order to do this safely, they said they needed to use a technique known as ECMO, or extracorporeal membrane oxygenation – basically a machine that allows them to oxygenate blood without sending it to the lungs.

Rather than subject the child to this risky procedure, Dr. Jacob and the surgeon decided to just take a piece of the lymph node out in order to make the diagnosis. Treatment of whatever the boy had would bring the size of the lymph node down.

Don’t Make a Move

When the boy was brought to the procedure room, the surgeon explained that he was going to put numbing medicine all around the bump in the boy’s neck and take out a piece of it. The child listened calmly and agreed.

He wasn’t to move at all, the surgeon explained. The child nodded solemnly. He understood. The boy was remarkably mature and so brave throughout the entire process of anesthetizing the region that the surgeon thought he might be able to continue and get the entire node out.

He paused in his surgery and consulted the parents. Would they allow him to try this? Their son was doing so well he was sure he could get it. They agreed, and the surgeon returned to his task. The lymph node came out without difficulty.

Photo

Credit

It was sent to the lab and the answer came back almost immediately. The swollen tissue was filled with the tiny coccidioides. You can see a picture of these little critters here.

A Year of Medicine

The boy was started on an intravenous medicine for fungal infections. Then after a week it was changed to one he could take by mouth.

Because the infection had spread beyond the lungs, the child will have to take this medication for a year. After starting the medication, the child began to look a little better. Slowly he was less tired. Slowly he started to eat the way he used to.

It was a long road to the diagnosis, and an even longer road to cure, but at least they were on the right one.

A Perfect Storm?

The mother called the ranch in Arizona where they stayed to let them know what had happened.
The owner told them that their son was not the only person visiting then who got sick. At least one other guest, there at the same time, had come down with the disease.

Apparently the conditions for spread were perfect. Their stay had started off with some rain, followed by heat and some brisk wind. The moisture helped the fungus grow; the heat dried it out so that it could become easily airborne and inhaled when lifted by the wind.

Although the family has loved their visits to this ranch – this was their second year – the child’s mother tells me that she’s not sure she’ll be going back, at least for a couple of years. Most people exposed to valley fever become immune forever, but because her little boy was so very sick, she’s planning to wait a while before they return.

Thumb Suckers and Nail Biters May Develop Fewer Allergies

Photo

Credit Getty Images

Babies have been seen sucking on their fingers in utero weeks before birth. But the sight of an older child with his fingers constantly in his mouth, sucking her thumb, biting his nails, can drive parents crazy, bringing up fears about everything from social stigma to germs.

A new study suggests that those habits in children ages 5 to 11 may indeed increase exposure to microbes, but that that may not be all bad.

When a pediatrician discusses thumb-sucking, it’s usually because a parent is worried. The thumb is in the mouth so constantly that there’s a worry about speech or about whether the teeth may be affected. It’s gone on too long, and an older child is being teased about it. And in those situations, especially when a child is over 4, we work with parents and children on how to break the habit.

Nail biting worries parents for similar reasons, and we often end up giving similar advice: Don’t make negative comments; look for the situations that bring on the behavior and find alternate strategies; praise and reward the child for not doing it; put a glove or a bandage on the hand to remind the child.

In a study published Monday in the journal Pediatrics, researchers drew evidence from an ongoing study of New Zealand children to show those whose parents described them as thumb-suckers and nail-biters were less likely to have positive allergic skin tests later in life.

The children were in the Dunedin Multidisciplinary Health and Development Study, in which 1,037 children born in 1972-73 in Dunedin, a coastal city in New Zealand, were assessed and tested as they grew up, with the most recent assessment done at age 38. Stephanie Lynch, a student at Dunedin School of Medicine and the first author of the paper, had the idea of using the data to look at a possible relationship between children who tend to have their fingers in their mouths and allergic sensitization.

The question of such a connection arose because of the so-called hygiene hypothesis, an idea originally formulated in 1989, that there may be a link between atopic disease — the revved-up action of the immune system responsible for eczema, asthma and allergy — and a lack of exposure to various microbes early in life. Some exposure to germs, the argument goes, may help program a child’s immune system to fight disease, rather than develop allergies.

In the study, parents were asked about their children’s nail-biting and thumb-sucking habits when the children were 5, 7, 9 and 11 years old. Skin testing for allergic sensitization to a range of common allergens including dust mites, grass, cats, dogs, horses and common molds was done when the children were 13 years old, and then later when they were 32. Thirty-one percent of the children were described as “frequent” nail biters or thumb suckers (or both) at one or more of those ages.

The study found that children who frequently sucked a thumb or bit their nails were significantly less likely to have positive allergic skin tests both at 13 and again at 32. Children with both habits were even less likely to have a positive skin test than those with only one of the habits.

These differences could not be explained by other factors that are associated with allergic risk. The researchers controlled for pets, parents with allergies, breast-feeding, socioeconomic status and more. But though the former thumb-suckers and nail-biters were less likely to show allergic sensitization, there was no significant difference in their likelihood of having asthma or hay fever.

Robert J. Hancox, one of the authors of the study, is an associate professor in the Department of Preventive and Social Medicine at Dunedin School of Medicine, a department that is particularly oriented toward the study of diseases’ causes and risk factors. He said in an email, “The hygiene hypothesis is interesting because it suggests that lifestyle factors may be responsible for the rise in allergic diseases in recent decades. Obviously hygiene has very many benefits, but perhaps this is a downside. The hygiene hypothesis is still unproven and controversial, but this is another piece of evidence that it could be true.”

Malcolm Sears, one of the authors of the paper, a professor of medicine at McMaster University in Hamilton, Ontario, who was the original leader for the asthma allergy component of the New Zealand study, said, “Early exposure in many areas is looking as if it’s more protective than hazardous, and I think we’ve just added one more interesting piece to that information.”

Dr. Hancox pointed out that the study does not show any mechanism to account for the association. “Even if we assume that the protective effect is due to exposure to microbial organisms, we don’t know which organisms are beneficial or how they actually influence immune function in this way.”

Thumb sucking, especially in an older child, can still be a problem if it interferes with the teeth, or causes infections on the fingers, or gets a child teased. Lynn Davidson, a developmental pediatrician who is an attending physician at the Children’s Hospital at Montefiore in the Bronx, and the author of a review article on thumb sucking, said she tends to be “very low-key” about thumb sucking, since children often stop on their own as they grow.

With older children, Dr. Davidson suggests that parents, if they are worried, should try to analyze when and why the child resorts to thumb sucking or nail biting, and then try behavioral techniques, like offering a child a foam ball to hold and squeeze at those moments. “In an older child you can use their input, ask, what would you do with your hands instead of putting them in your mouth,” she said.

Dr. Sears said, “My excitement is not so much that sucking your thumb is good as that it shows the power of a longitudinal study.” (A longitudinal study is one that gathers data from the same subjects repeatedly over a period of time.) And in fact, as researchers tease out the complex ramifications of childhood exposures, it’s intriguing to look at long-term associations between childhood behavior and adult immune function, by watching what happens over decades.

So perhaps the results of this study help us look at these habits with slightly different eyes, as pieces of a complicated lifelong relationship between children and the environments they sample as they grow, which shape their health and their physiology in lasting ways.

Day Care Infections May Mean Fewer Sick Days Later

Photo

Credit Getty Images

All three of my children started out in day care as infants, and the day care center was, in so many ways, at the center of our lives for years. The teachers taught us most of what we knew about young children (including, I am sorry to say, the difference between well-meaning parents and truly talented professionals). The day care cohort provided my children with their close friends (who keep turning up in their high school and college classes). We even bought our house so we could live near the day care center.

But yes, there were the infections. The worst battles my husband and I had were fought when a small child had to stay home with fever or diarrhea, and we had the eternally nasty whose-work-day-is-more-important-mine-or-yours-and-just-what-makes-you-think-so discussion. On the other hand, as our children got a little bigger, the infections essentially vanished — they had nearly perfect attendance records by the time they got to kindergarten and beyond.

In a study published last month in the journal Pediatrics, researchers in the Netherlands followed a large group of children over the first six years of their lives, looking at how often doctors diagnosed acute gastroenteritis, the stomach bugs so familiar to parents; 1,344 out of the total 2,220 children studied attended day care during the first year of life. Being in day care as an infant increased a child’s risk of having acute gastroenteritis in the first year of life, but it also had a protective effect after that.

Interestingly, the protective effect lasted at least till age 6, which is as far as the study went; the children who were in day care by the age of 1 had more gastroenteritis earlier, but the non-day care children got sick more often as they got older. By age 6, children in the two groups averaged similar numbers of total episodes.

“We think if you are infected at an early age you build up immunity against these viruses or bacteria,” said Marieke de Hoog, an epidemiologist at University Medical Center Utrecht and the senior author on the study. “There is even a possibility that the protective effect we have seen will continue when children grow up — we need more research.”

Day care attendance is known to be a risk factor for upper respiratory infections, which are much more frequent than gastroenteritis — the average child may have as many as eight upper respiratory infections a year, to maybe one bout of gastroenteritis, said Dr. Timothy Shope, an associate professor of pediatrics at Children’s Hospital of Pittsburgh, who is the co-editor of the American Academy of Pediatrics book Managing Infectious Diseases in Childcare and Schools: A Quick Reference Guide,” the fourth edition of which is due out next month. And going to day care also puts a child at higher risk for the ear infections that can follow those upper respiratory infections.

In fact, the gastroenteritis study from the Netherlands was an offshoot of a larger study focused on respiratory infections in children, and Dr. de Hoog and her colleagues published an article in 2014 in which they demonstrated a similar pattern in upper respiratory infections and ear infections: Children who attended day care in the first year of life had more infections earlier and fewer later. For the early day care group, this led to more doctor visits overall, and more antibiotics.

Some infections can be more severe or more dangerous in babies, which is probably one reason children who get sick younger get more medical attention. And there can certainly be moments in those early years of day care when, even though children are not dangerously ill, parents can feel overwhelmed by the parade of runny noses and runny bowel movements.

There is a more complex relationship between day care attendance and the risk of developing asthma and eczema, where there are several other important factors, like family history, antibiotic exposure, and the risk of infection with one particular virus called respiratory syncytial virus, or R.S.V., which has been linked to developing asthma. Still, Dr. Shope said, day care attendance may protect against these so-called “atopic” diseases, which are related to hypersensitivity reactions in which the body’s immune system is overreactive, and it has been suggested that this connects to the “hygiene hypothesis,” that early exposures may be beneficial for the immune system.

There are three basic lines of prevention for bringing down the frequency of infections in day care children, and the most effective is immunization. We immunize against several of the most common organisms that cause gastroenteritis (oh, how I wish there had been a vaccine against rotavirus when my children were born — that diarrhea lasted for weeks) and also against some of the organisms that can complicate respiratory infections. But we have to get better at making sure all young children get the influenza vaccine, which unfortunately has to be given every year, since the virus is particularly dangerous to children.

Infection control is also important in day care, especially around diaper changing and hand-washing. However, there are limits to how much young children can cooperate regarding what they put in their mouths, or whether they cover their coughs. Studies show some benefit of infection control measures, but “not as much as we would like,” Dr. Shope said.

Then there is the always complex pediatric decision about who needs to stay home. Although there are very specific recommendations around diarrhea and diaper changing, for example, it’s also true that with many viral illnesses, children are infectious before symptoms develop and after they cease, while other children are infected and infectious but never develop symptoms, so the protective value of excluding the symptomatic children is limited.

I often see parents who are told their children have to stay home from day care, and I still identify with them. So does Dr. Shope. “When I’m seeing a typical parent with a child under a year who’s in child care, and they’re missing work, they’re wondering if something is wrong with the child,” he told me. “I tell them this is normal, they’re making an investment for the future, their child is less likely to be ill going into kindergarten when other children raised with less contact are more likely to be ill.”

Related:

Interested in more Well Family? Sign up to get the latest news on parenting, child health and relationships with advice from our experts to help every family live well.

Post-Cesarean Bacteria Transfer Could Change Health for Life, Study Shows

Photo

Credit iStock

The first germs to colonize a newborn delivered vaginally come almost exclusively from its mother. But the first to reach an infant born by cesarean section come mostly from the environment — particularly bacteria from inaccessible or less-scrubbed areas like lamps and walls, and skin cells from everyone else in the delivery room.

That difference, some experts believe, could influence a child’s lifelong health. Now, in the first study of its kind, researchers on Monday confirmed that a mother’s beneficial microbes can be transferred, at least partially, from her vagina to her baby after a C-section.

The small proof-of-principle study suggests a new way to inoculate babies, said Dr. Maria Gloria Dominguez-Bello, an associate professor of medicine at New York University and lead author of the report, published on Monday in Nature Medicine.

“The study is extremely important,” said Dr. Jack Gilbert, a microbial ecologist at Argonne National Laboratory who did not take part in the work. “Just understanding that it’s possible is exciting.”

But it will take further studies following C-section babies for many years to know to what degree, if any, the method protects them from immune and metabolic problems, he said.

Some epidemiological studies have suggested that C-section babies may have an elevated risk for developing immune and metabolic disorders, including Type 1 diabetes, allergies, asthma and obesity.

Scientists have theorized that these children may be missing key bacteria known to play a large role in shaping the immune system from the moment of birth onward. To replace these microbes, some parents have turned to a novel procedure called vaginal microbial transfer.

A mother’s vaginal fluids — loaded with one such essential bacterium, lactobacillus, that helps digest human milk — are collected before surgery and swabbed all over the infant a minute or two after birth.

An infant’s first exposure to microbes may educate the early immune system to recognize friend from foe, Dr. Dominguez-Bello said.

Friendly bacteria, like lactobacilli, are tolerated as being like oneself. Those from hospital ventilation vents or the like may be perceived as enemies and be attacked.

These early microbial interactions may help set up an immune system that recognizes “self” from “non-self” for the rest of a person’s life, Dr. Dominguez-Bello said.

In the United States, about one in three babies are delivered by C-section, a rate that has risen dramatically in recent decades. Some hospitals perform the surgery on nearly seven in ten women delivering babies.

An ideal C-section rate for low-risk births should be no more than 15 percent, according to the World Health Organization.

Dr. Dominguez-Bello’s study involved 18 babies born at the University of Puerto Rico hospital in San Juan, where she recently worked. Seven were born vaginally and 11 by elective C-section. Of the latter, four were swabbed with the mother’s vaginal microbes and seven were not.

Microbes were collected on a folded sterile piece of gauze that was dipped in a saline solution and inserted into each mother’s vagina for one hour before surgery. As the operations began, the gauze was pulled out and placed in a sterile collector.

One to two minutes after the babies were delivered and put under a neonatal lamp, researchers swabbed each infant’s lips, face, chest, arms, legs, back, genitals and anal region with the damp gauze. The procedure took 15 seconds.

Dr. Dominguez-Bello and her colleagues then tracked the composition of microbes by taking more than 1,500 oral, skin and anal samples from the newborns, as well as vaginal samples from the mothers, over the first month after birth.

For the first few days, ambient skin bacteria from the delivery room predominated in the mouths and on the skin of C-section babies who were not swabbed, Dr. Dominguez-Bello said.

But in terms of their bacterial colonies, the infants swabbed with the microbes closely resembled vaginally delivered babies, she found, especially in the first week of life. They were all covered with lactobacilli.

Gut bacteria in both C-section groups, however, were less abundant than that found in the vaginally delivered babies.

Anal samples from the swabbed group, oddly, contained the highest abundance of bacteria usually found in the mouth.

The results show the complexity of labor, said Dr. Alexander Khoruts, a microbial expert and associate professor of medicine at the University of Minnesota. “It cannot be simplified to a neat, effortless passage of the infant through the birth canal,” he said.

As the month progressed, the oral and skin microbes of all infants began to resemble normal adult patterns, Dr. Dominguez-Bello said. But fecal bacteria did not, probably because of breast or formula feeding and the absence of solid foods.

The transfer fell short of full vaginal birth-like colonization for two reasons, Dr. Dominguez-Bello said. Compared to infants who spent time squeezed inside the birth canal, those who were swabbed got less exposure to their mother’s microbes.

And all infants delivered by C-section were exposed to antibiotics, which also may have reduced the number and variety of bacteria colonizing them.

A larger study of vaginal microbial transfer is underway at N.Y.U., Dr. Dominguez-Bello said. Eighty-four mothers have participated so far.

Infants delivered both by C-section and vaginally will be followed for one year to look for differences in the treated and untreated groups and to look for complications. Thus far the swabbing has proved entirely safe.

The procedure is not yet recommended by professional medical societies, said Dr. Sara Brubaker, a specialist in maternal and fetal medicine at N.Y.U. Until more is known, physicians are hesitant to participate.

“But it has hit the lay press,” she said. “Patients come in and ask for it. They are doing it themselves.”

Dr. Brubaker is one of them. When her daughter was born three-and-half months ago, she arranged to have her baby swabbed.

For more fitness, food and wellness news, follow us on Facebook and Twitter, or sign up for our newsletter.