Covid-19 Live Updates: Pfizer Vaccine Boosters, Omicron And Cases – The New York Times

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Federal regulators on Thursday authorized booster shots of the Pfizer-BioNTech coronavirus vaccine for 16- and 17-year-olds, at least six months after they received their second shot of that vaccine. The move clears the way for several million teenagers to receive an additional shot.

All adults have been eligible since Nov. 19 to receive a booster six months after their second shot of Pfizer or Moderna’s vaccines, or two months after a Johnson & Johnson shot. Nearly 50 million Americans — or one fourth of those fully vaccinated — have gotten the additional shots.

The Food and Drug Administration broadened Pfizer’s authorization to cover the younger age group on an emergency basis. The other two coronavirus vaccines, Moderna and Johnson & Johnson, are authorized for use only for adults.

The agency’s decision, which was expected, comes as an initial spate of laboratory tests have suggested that the new fast-spreading variant, Omicron, seemed to dull the power of two doses of the Pfizer vaccine.

“Since we first authorized the vaccine, new evidence indicates that vaccine effectiveness against Covid-19 is waning after the second dose of the vaccine for all adults and for those in the 16- and 17-year-old age group,” said Dr. Peter Marks, who oversees the F.D.A.’s vaccine division. A booster “will help provide continued protection against Covid-19 in this and older age groups,” he added.

The Centers for Disease Control and Prevention, which sets vaccine policy for the federal government, is considered likely to promptly endorse the F.D.A.’s action, according to people familiar with the agency’s planning. Neither the F.D.A.’s nor the C.D.C.’s vaccine expert advisory panels is expected to meet to discuss the move, as they typically have before eligibility for shots has been expanded.

Those meetings would have given regulators and experts a chance to publicly discuss the merits of the move, including a review of safety data gathered on adolescents who had received the Pfizer-BioNTech vaccine.

Pfizer and BioNTech said Wednesday that tests with blood samples from people who had received only two doses showed much lower levels of virus-fighting antibodies against Omicron than against an earlier version of the virus. Antibodies are the immune system’s first line of defense against the virus, and the results suggest that two doses may not be sufficient to protect against infection, the companies said.

With a booster, the level of antibodies working to neutralize the Omicron variant were comparable to those combating the original variant after two doses, the companies said.

Senior administration health officials have said Omicron, which contains dozens of mutations never seen before, is even more reason for everyone eligible for a booster to get one. More than 200 million Americans — over 60 percent of the population — have been fully vaccinated.

Although the U.S. vaccination rate overall is still well behind that of some other countries, the discovery of Omicron has driven many people to get shots, even as much remain unknown about the variant.

Support for boosters has been growing among public health experts in the face of the Omicron variant; some who previously opposed them now support a broad campaign. The F.D.A.’s expert committee rejected Pfizer-BioNTech’s request in September to clear a booster shot for 16 and 17 year olds, partly because of concerns over what they saw as insufficient data about a rare heart condition tied to the Pfizer-BioNTech and Moderna shots, especially in younger men.

That condition, myocarditis, or inflammation of the heart muscle, can also be caused by the virus. Federal scientists have said that cases tend to be mild and resolve quickly.

According to federal data, about 5.5 million teenagers aged 16 to 17 — two-thirds of that age group — have received at least one dose of Pfizer’s vaccine. More than 4.7 million have received two doses. Roughly three million got their second shot at least six months ago and would be eligible for a third shot this month.

Dr. Ugur Sahin, the chief executive of BioNTech, Pfizer’s German partner, said: “In the current situation, it is important to offer everyone a booster, particularly against the background of the newly emerging variants such as Omicron.” Dr. Albert Bourla, the chief executive of Pfizer, called the expansion of booster shots “a critical milestone.”

Pfizer is supplying booster doses to the United States government under an agreement negotiated months ago.

“The companies do not expect that today’s news will impact the existing supply agreements in place with governments and international health organizations,” a statement released Thursday by Pfizer said.

As the emergence of the Omicron variant of the coronavirus has spurred governments of wealthy nations to step up booster-shot campaigns, the World Health Organization again expressed concern on Thursday that the push could further undermine global vaccine equity.

“Broad-based administration of booster doses risks exacerbating inequities in vaccine access,” Alejandro Cravioto, chairman of the W.H.O.’s Strategic Advisory Group of Experts on Immunization, told reporters.

The administration of boosters is now outpacing first shots around the world.

According to Richard Mihigo, coordinator for the W.H.O.’s Immunization and Vaccines Development Program in Africa, “If we looked at the data today, even before Omicron, we are seeing high-income countries administering more booster doses than even vaccines that are being given in developing countries.”

Because most current infections, which are still overwhelmingly being driven by the Delta variant, are affecting unvaccinated people, the W.H.O. said, getting vaccines to those who have no protection should be the priority.

“Remember that we only have 8 percent — 8 percent — of people who have been fully vaccinated in this region,” Mr. Mihigo said of Africa. “This represents around 103 million people in a continent of 1.3 billion.”

Worldwide, about 73 percent of shots that have gone into arms have been administered in high- and upper-middle-income countries, according to the Our World in Data project at the University of Oxford. Only 0.8 percent of doses have been administered in low-income countries.

The W.H.O.’s reticence on boosters has put it out of step with governments around the world. Data from both Israel and Britain has shown that an extra vaccine dose can sharply lower a person’s likelihood of catching the coronavirus and getting sick, leading many countries to expand their booster programs.

The W.H.O. advisory group said on Thursday that preliminary data has suggested that extra shots could be useful if administered to older or immunosuppressed people. However, Mr. Mihigo said that, at the moment, there appeared to be “very little benefit of the booster dose for the younger population.”

Now scientists are racing to understand how Omicron might affect the pandemic and to determine the effectiveness of vaccines in combating its spread and preventing serious illness and death.

Pfizer and BioNTech said on Wednesday that laboratory tests suggested a booster shot of their coronavirus vaccine offered significant protection against the fast-spreading variant.

While limited in scope, the findings provided a bit of hopeful news at a time of renewed uncertainty. Blood samples obtained from people who had received a booster shot contained antibodies neutralizing Omicron at levels comparable with those combating the original variant after two doses, Pfizer’s statement said. While antibodies are the first line of defense against infection, they are only part of a wider-ranging and powerful response by the immune system. Because antibodies are the fastest and easiest part to measure, those results typically come first.

President Biden called Pfizer’s data “encouraging,” adding on Twitter, “This reinforces what my medical advisors have been emphasizing: that boosters give you the highest protection yet.”

The W.H.O. has cautioned about the risks that booster campaigns present as tens of millions in lower-income countries have not had access to a single dose.

Dr. Kate O’Brien, the W.H.O.’s vaccine director, said that in the face of the Omicron variant, there was a risk that wealthy countries would go back to hoarding vaccine supplies.

But Andrea Taylor, who tracks vaccine production for the Duke Global Health Innovation Center, said that while it was hard to know the true status of vaccine supply and delivery because of a lack of transparency, booster campaigns should not significantly affect supplies for lower-income countries.

“Globally, we are producing a staggering 1.5 billion doses a month, and we theoretically have enough doses now to provide boosters across wealthy countries, as well as first and second doses to at least 40 percent of the population in other countries,” she said. “In reality, however, these doses are not where they need to be.”

“Too many of them are sitting unused in wealthy countries,” she said, adding that estimates showed that the world’s wealthiest nations would have about 770 million excess doses on hand at the end of this month.

Dr. O’Brien noted that efforts by wealthy countries to donate surplus vaccines had been threatened because the doses they were offering have a relatively short shelf life.

Many poorer countries, especially in Africa, are finding they do not have the capacity to get shots in arms before they expire.

Health officials may be bracing for the Omicron variant to sweep through the country, but the Delta variant remains the more imminent threat as it continues to drive an increase in hospitalizations.

Health care workers said their situations had been worsened by staff shortages brought on by burnout, illnesses and resistance to vaccine mandates.

More than 55,000 coronavirus patients are hospitalized nationwide, far fewer than in September, but an increase of more than 15 percent over the past two weeks, according to a New York Times database. The United States is averaging about 121,300 coronavirus cases a day, an increase of about 27 percent from two weeks ago, and reported deaths are up 12 percent, to an average of about 1,275 per day.

Michigan, which now leads the country in hospitalizations per capita, announced last month that the federal government was sending health care workers to support some hospitals. On Wednesday, Vermont had a record of about 90 people hospitalized with Covid-19, according to the state’s health department. And cases and hospitalizations are rising fastest in Connecticut, which recorded a 69 percent increase in patients in the past two weeks.

Even states that rank among the highest in vaccination rates are struggling, like Maine, where about 73 percent of the population is fully vaccinated, behind only Vermont and Rhode Island, according to a New York Times database. Cases in Maine recently reached their pandemic peak.

On Wednesday, with Maine’s hospitals straining, Gov. Janet Mills activated as many as 75 members of the state’s National Guard to help. The Guard members, she said, would support nursing facilities and administer monoclonal antibodies, which help prevent serious illness.

“I do not take this action lightly,” Ms. Mills said in a statement. “But we must take steps to alleviate the strain on our health care system and ensure care for all those who need it.”

Maine Medical Center, the state’s largest hospital, said in a statement on Wednesday that there had been times this week “when there were no critical care beds available,” forcing hospital leaders to postpone surgeries.

“We are caring for an unprecedented number of patients,” the hospital said.

Gov. Chris Sununu of New Hampshire took similar steps Wednesday, saying at a news conference that 70 National Guard members in his state would be deployed in the next few weeks to help the state’s straining hospitals with nonmedical functions like food service and clerical work. On top of that, the governor said, the Federal Emergency Management Agency was dispatching a team of 24 people to assist the hardest-hit facilities.

New York State turned to National Guard troops last week to help reinforce overburdened nursing homes around the state.

In Missouri, officials are reporting burnout among health care workers.

Dr. Raghu Adiga, the chief medical officer at Liberty Hospital in Liberty, Mo., said on Wednesday that his staff was frustrated with those who were unvaccinated because they were driving this latest surge.

“They’re going to have to help us help them,” Dr. Adiga said.

More than 1,600 people in Missouri were hospitalized with Covid as of Wednesday, compared with about 980 on Nov. 8, data shows.

Missouri’s University Health hospital system had 10 people hospitalized with Covid in early November, said Dr. Mark Steele, the system’s chief medical officer. On Wednesday, there were 39.

“What we’re seeing now is still overwhelmingly the Delta variant,” Dr. Steele said, adding that now, there are “concerns about Omicron” to think about.

Leaders of a bipartisan coalition of experts in education, the economy and health have been meeting with White House officials, pressing for new initiatives specifically for the tens of thousands of children who have lost parents and primary caregivers to Covid-19.

On Thursday, the group, the Covid Collaborative, released a report estimating that more than 167,000 children in the United States have lost parents or in-home caregivers to the disease. The group is backed by wealthy philanthropies and headed by two former governors, Dirk Kempthorne of Idaho, a Republican, and Deval Patrick of Massachusetts, a Democrat.

The collaborative is asking President Biden to initiate a national campaign to identify these children and, with help from the private sector, take steps to improve their emotional and economic well-being. Its recommendations include offering them mental health care and creating a “Covid Bereaved Children’s Fund,” similar to a fund established after the Sept. 11 attacks, to provide up to $10,000 to families in need.

“The president is uniquely positioned to put an official imprimatur on the call in this report to coordinate all resources, public and private, at every level of government and every level of the private sector and philanthropy to help these children,” Mr. Patrick said in an interview.

“It’s a tragedy not of their making,” he added, “but they’re our kids. They belong to us, and all we are saying is, ‘Let’s act like it.’”

Among the trillions of dollars Congress has allocated to combat the pandemic, more than $100 million has gone to existing children’s mental health programs and some $122 billion for schools.

The government itself has pointed to the need for more help for the country’s children. On Tuesday, the surgeon general warned that young people were facing “devastating” mental health issues related to the pandemic.

More than 200 million Americans — over 60 percent of the population — have been fully vaccinated against the coronavirus.

The United States crossed that milestone as the threat of the Omicron variant spurred a flurry of jabs in recent days, though the daily rate remains far below its peak in April. And the U.S. lags significantly behind several other countries, which have inoculated over 80 percent of their populations.

Providers are administering about 1.78 million doses per day on average, including first, second and additional doses, about a 47 percent decrease from the peak of 3.38 million reported on April 13, according to federal data.

The United States remains far behind not only developed countries like Singapore and Portugal, which will soon have vaccinated 90 percent of their populations, but developing nations like Cambodia (over 80 percent), according to Our World in Data.

Even before the arrival of Omicron, cases and hospitalizations were on the rise in the U.S. as the weather grew colder in much of the country and the highly contagious Delta variant remained a threat. Daily cases are averaging over 120,000 and more than 55,000 patients are hospitalized nationwide, far fewer than in September but an increase of more than 15 percent over the last two weeks. Hospitals have been overstretched from upstate New York to New Mexico.

The U.S. has been ahead of other countries in booster shots, which it authorized in September and October for many Americans. Then on Oct. 29, the Food and Drug Administration cleared the Pfizer vaccine for children ages 5 to 11.

The daily rate of Americans getting their shots had been steadily climbing since the government widened eligibility and has soared since Thanksgiving, when the Omicron variant was discovered. With dozens of mutations never before seen, Omicron was named a variant of concern by the World Health Organization.

Scientists have feared that the fast-spreading variant could evade the protection of vaccines. But on Wednesday, Pfizer and BioNTech said laboratory tests suggested that three doses of their coronavirus vaccine offered significant protection against Omicron. The lab experiments don’t indicate with any certainty how the vaccines will perform in the real world, and scientists say it could take a month or more to understand the new variant’s threat.

Many questions remain about Omicron.

There are early signs that it may cause only mild illness, though that observation was based mainly on cases in South Africa among young people, who are generally less likely to become severely ill from Covid. Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, told The Associated Press on Wednesday that while the data is very limited, “the disease is mild” in almost all of the U.S. cases recorded so far. Reported symptoms have mainly been cough, congestion and fatigue and some cases have grown more severe over time, she said.

Scientists are also waiting to see whether cases lead to more hospitalizations and deaths; both lag surges in infections by days or weeks.

Broad mandates by President Biden that had helped boost vaccination rates have been put on hold by courts.

Americans who have resisted getting vaccinated can be grouped into two categories, as a New York Times report showed in July.

In one are those who are adamant in their refusal; they include a mix of people but tend to be disproportionately white, rural, evangelical Christian and politically conservative, surveys show.

In the other are those who are persuadable, but say they have been putting off vaccination or want to wait and see before making a decision; they are a broad range of people, but tend to be a more diverse and urban group, including many younger people, Black and Latino Americans, and Democrats.

It’s this second group that health officials have made progress in inoculating, but surveys suggest they account for less than half of all unvaccinated adults in the United States.

— Ron DePasquale

As New York City’s arts and culture sector seeks to rebound from the economic devastation wrought by the pandemic, the Department of Cultural Affairs announced on Thursday that it would award $51.4 million in grants to more than 1,000 nonprofit arts organizations.

The grants, for the 2022 fiscal year, represent the largest-ever allocation for what is known as the Cultural Development Fund. Some of the grants will broadly increase funding for organizations that need a financial shot in the arm; other grants will offer more targeted support of disability arts, language access, arts education and more.

Officials also said that a chunk of the money — about $5.1 million — is being sent to more than 650 groups working in underserved communities that were hard hit by the pandemic.

“This improved funding will encourage artists, creators and producers across the city to continue to express their insights and stories on their own terms,” Vicki Been, the deputy mayor for housing and economic development, said in a statement.

A survey of the effects of the coronavirus commissioned by the Department of Cultural Affairs in the spring of 2020 found that overall, about one in 10 arts organizations thought they would not survive the pandemic. Smaller organizations in particular were some of the hardest hit, according to the survey.

Some of the grants, of less than $10,000, have been awarded to small theater companies, choirs and museums. And to further help ensure that modestly sized groups and even individual artists receive a share of the funding, almost $3 million will be given to five local arts councils serving each borough. Those councils, in turn, will distribute the money to local constituents, city officials said.

But large organizations will also benefit. Some of the city’s most recognizable arts institutions like the Metropolitan Opera, the New York Philharmonic, the Solomon R. Guggenheim Museum and the 92nd Street Y are among the organizations that will receive some of the largest grants, in excess of $100,000 each.

The grants — $45.5 million in mayoral funds and $5.9 million in City Council member items — are part of what officials said was a roughly $230 million annual budget for the Department of Cultural Affairs.

“Culture is essential to healthy, vibrant neighborhoods, and there is no recovery for New York City without our cultural community,” Gonzalo Casals, the city’s cultural affairs commissioner, said.

Sarah Bahr contributed reporting.

DETROIT — Caitlin Reynolds, a single mother, was happy that her son, L.J., was finally settled into fourth grade after a rocky experience last year with remote learning.

Then, on Wednesday, Nov. 17, came an announcement: Detroit public schools would close their classrooms every Friday in December. There would be virtual school only. On Friday, another announcement: School was canceled starting that Monday, for the entire week of Thanksgiving. This time, there would be no online option.

After a few months of relative calm, some public schools are going remote — or canceling class entirely — once a week, or even for a few weeks, because of teacher burnout or staff shortages. Several Michigan districts extended Thanksgiving break; three in Washington State unexpectedly closed on Nov. 12, the day after Veterans Day; and in Florida, Brevard schools used leftover “hurricane days” to close schools Thanksgiving week. Some closings have occurred with little notice, causing major logistical problems for parents and worries that children will fall further behind.

For many districts, remote learning days are a last-ditch effort to prevent teachers who say they are burned out from resigning after a tough year of working with learning loss, and putting in overtime to make up for labor shortages.

Battles in the classroom — over mask mandates and critical race theory — have also taken a toll, said Randi Weingarten, the president of the American Federation of Teachers, the country’s second-largest teachers’ union.

“What you hear from teachers is that it’s been too much,” she said. “And they’re trying the best that they can.”

Parents say they are doing the same, but for some it comes down to being home when school is canceled on short notice or losing pay or stature at work.

“It’s very difficult already being a single parent, period,” said Kristina Morgan of Southfield, Mich., who works for the Wayne County courts and, when school is canceled on short notice, relies on relatives to care for her daughter Kennedy Martinez. If no one is available, she must take the day off work, which reflects poorly on her at the office. “When you have your life figured out based on your child being in school during certain hours — and when I have to scramble to find child care outside of those hours, or to ask around — it’s frustrating,” she said.

Prime Minister Sanna Marin of Finland apologized late Wednesday after photographs surfaced of her dancing maskless in a nightclub on Saturday night, one day after she came into contact with a government official who had tested positive for the coronavirus.

“I did wrong,” she said in a television interview on the public broadcaster Yle. “I should have considered the situation more carefully.”

Coronavirus restrictions in Finland, as in many European countries, have evolved and changed over the past two years. Currently, those who are double vaccinated, like Ms. Marin, do not need to isolate after coming into contact with someone who tests positive for the virus.

But separate guidelines for government ministers and employees recommend that they limit social contact immediately after exposure, according to Finland’s Helsingin Sanomat newspaper.

When images of Ms. Marin at the nightclub, in Helsinki, were made public this week, they quickly went viral.

Writing on Facebook, Ms. Marin said she was told by an official that the coronavirus rules did not require her to isolate, despite having been in contact with an infected person.

“I should have used better judgment and double-checked the guidance given to me,” she wrote. “I am very sorry for not understanding that I needed to do that.”

Ms. Marin has not tested positive for the virus.

Throughout the pandemic, Finland has had some of lowest infection rates in Europe. The country, with a population of about 5.5 million, has recorded roughly 196,000 cases of infection and 1,384 deaths, according to Our World in Data.

Ms. Marin, now 36, became the world’s youngest sitting prime minister when she was sworn into office two years ago. She heads a government that is remarkably female and young: The other four major parties in the government are led by women, three of whom are, like the prime minister, under 40.

The detection of the Omicron variant has brought renewed attention, and a new urgency, to the worldwide Covid-19 vaccination campaign, which experts say remains among the most powerful tools at our disposal when it comes to preventing dangerous new variants.

Most wealthy countries have vaccinated significant shares of their populations and have rapidly moved into the booster-dose phase. But one year into the global vaccine rollout, the gap between vaccination rates in high- and low-income countries is wider than ever.

Poorly vaccinated countries face several challenges. Early in the rollout process, some countries were not able to secure enough doses to inoculate their residents, and many still face shortages. In others, supply is only part of the story. A New York Times analysis of available data highlights the countries where infrastructure issues and the public’s level of willingness to get vaccinated may pose larger obstacles than supply.

UNICEF, perhaps the most recognized arm of the United Nations, is commemorating its birthday with the most sobering of messages: The pandemic is the worst threat to gains made for children since the agency was created to help them 75 years ago.

The United Nations Children’s Fund, as UNICEF is formally known, said in a report released Wednesday evening that because of the coronavirus, the number of children who are hungry, out of school, abused, impoverished and forced into marriage is rising. At the same time, the number with access to health care, vaccines, enough food and essential services is falling.

Even in the best-case projection, the report said, it would take seven to eight years just to return to pre-Covid poverty levels for children.

Henrietta Fore, UNICEF’s executive director, said in the report that the basic improvements in children’s lives accomplished since the agency’s formation in the ashes of World War II “are now at risk” from the ravages of Covid-19.

The report cites, for example, evidence that 100 million children have fallen into poverty since the pandemic began, more than 23 million missed getting basic vaccines, and more than eight million have been forced into labor.

“In a year in which we should be looking forward, we are going backward,” Ms. Fore said. She called the pandemic “the biggest threat to progress for children in our 75-year history.”

Originally known as the United Nations International Children’s Emergency Fund, UNICEF was officially created by a General Assembly resolution on Dec. 11, 1946, as a temporary way to help alleviate the postwar suffering of millions of children.

In 1953, its status was extended indefinitely, and the agency was given what became its own iconic logo, depicting a child drinking milk. The logo evolved further in the 1960s as UNICEF’s work expanded, showing a mother lifting a child.

The agency is one of the world’s leading humanitarian providers, with annual expenditures exceeding $6.5 billion and a staff of more than 15,000 in more than 190 countries.

The Food and Drug Administration on Wednesday authorized the first drug for widespread use in preventing Covid in Americans with weakened immune systems who have not been adequately protected by vaccines.

The antibody treatment, which was developed by AstraZeneca and will be sold under the brand name Evusheld, is engineered to be “long-acting,” meaning the body metabolizes it more slowly so that it can stay active for months. That is expected to offer longer-lasting protection — perhaps for half a year — compared to the monoclonal antibody treatments that are given to high-risk people already sick with Covid.

The F.D.A. authorized AstraZeneca’s treatment for people with immune problems, a group that includes blood cancer patients, transplant recipients and people taking drugs that suppress the immune system. The authorization also included the very small number of people for whom vaccines are not recommended because they are allergic to Covid vaccines or their ingredients.

The United States has contracted with AstraZeneca to buy up to 700,000 doses of the treatment. A Biden administration health official said the doses will be allocated proportionally to states and that the first doses will begin to be distributed at no cost within the next few weeks.

“People who are immunocompromised have spent the last year not celebrating the vaccine but instead being more and more afraid of getting Covid and the implications of getting Covid,” said Dr. Dorry Segev, a transplant surgeon at Johns Hopkins University. “The immunocompromised population has been waiting for this for months and begging for this for months.”

Scientists are scrambling to run lab experiments to see how well Evusheld and other antibody treatments hold up to the Omicron variant, which has caused alarm because it contains mutations in the spike protein that is the target of some Covid drugs. AstraZeneca said that the mutations relevant to its treatment that have been tested so far in experiments do not suggest that the drug’s effectiveness will be significantly weakened against the variant.

AstraZeneca’s treatment is given via an intramuscular injection, like vaccines. It was shown to be strongly effective at preventing Covid in a clinical trial, reducing the risk of developing a symptomatic infection by 83 percent. That study mostly enrolled people who were at high risk of getting Covid, but the company has not broken out the results for people with immune problems.

A growing body of research has shown that many people with weak immune systems do not respond well to Covid vaccines, leaving them vulnerable to infection. The F.D.A. authorized third shots for such people long before they were recommended for the general population, but even three shots may not be enough for some.

An estimated 5 percent of the population is considered to be immunocompromised. Dr. Segev estimated that that has translated into millions of Americans who are not sufficiently protected by vaccines. AstraZeneca estimated that about five million people in the United States may benefit from its drug.

The F.D.A. said that Evusheld may be effective at preventing Covid for six months. That is thought to be longer than the protection provided by another antibody drug, from Regeneron, that the F.D.A. authorized over the summer to prevent Covid-19 in a limited number of patients with compromised immune systems who had not yet been exposed to the virus. They were at high risk of exposure as a result of living in nursing homes, prisons, or under similar conditions.

The vast majority of people with immune-system problems have become eligible for monoclonal antibody treatments, which are typically infused at a hospital or clinic, only after they had already been exposed to the virus or gotten sick.

JOHANNESBURG — The children had gone to the hospital for various reasons: One had jaundice, another malaria. A third had a broken bone. But once they were admitted, they all tested positive for the coronavirus, a worrying trend in South African hospitals that hints at how transmissible the new variant, Omicron, may be.

The doctors in the children’s wards of two large hospitals in Johannesburg say they have not seen a spike in admissions, and they still do not know whether the children have Omicron. But the increase in the number of those who test positive after coming in may provide a glimpse into the behavior of the heavily mutated variant that was discovered just last month, and about which little is known.

“Our suspicion is that Covid positivity rates in the community setting are very, very high at the moment and increasing,” said Dr. Gary Reubenson, a pediatrician at the Rahima Moosa Mother and Child Hospital in Johannesburg.

Young children under 12 are not yet eligible for Covid-19 vaccines in South Africa, which also leaves them more vulnerable.

While it is still too soon to draw any conclusions about the severity of the illness caused by Omicron, early modeling and analysis suggest that it may move twice as fast as the Delta variant.

“What is scary now is the proportion of patients who are positive among those who are admitted is very high,” said Dr. Sithembiso Velaphi, who works at the Chris Hani Baragwanath Hospital in Soweto. “The number of admissions overall has not increased.”

And although the number of young patients is relatively small, doctors noted that few of the children so far have needed oxygen.

The number of coronavirus cases in South Africa continues to rise exponentially in a fourth wave of infections that epidemiologists believe is driven by Omicron. Since the variant was first sequenced and announced by South African doctors on Nov. 25, it has become the dominant version among samples tested in the country.

— Lynsey Chutel