Scientific advisers to the Centers for Disease Control and Prevention are scheduled to meet on Wednesday to decide which Americans should get booster shots of the Pfizer-BioNTech coronavirus vaccine — and when.
The committee’s discussions are normally a scientific affair of little interest to most people. But this meeting is likely to be closely watched — the stakes are high. It follows a dramatic exchange at the Food and Drug Administration on Friday, when advisers overwhelmingly rejected a proposal to offer Pfizer booster shots for Americans over 16, but then voted unanimously in favor of third doses for some high-risk people and those older than 65.
The role of the C.D.C. advisers on Wednesday is to decide who belongs in those high-risk groups. Depending on their verdict, booster shots could be offered to most Americans — or only to a select few.
The decision may come as late as Thursday. But it is likely to be too late for the Biden administration, which had planned to begin offering third doses this week to most fully vaccinated adults in the United States.
At the meeting on Friday, senior scientists at Pfizer and the Israeli Ministry of Health presented data they said indicated waning immunity in people who received the Pfizer vaccine months earlier. Boosting immune defenses with a third shot has made a difference in Israel, they said, and could stem the tide of infections in the United States.
The F.D.A. advisers also evaluated data from the C.D.C. on the trajectory of the virus in the United States, as well as summaries from several studies on the effectiveness of the vaccines.
But after reviewing the evidence, the scientists on the committee concluded that while protection against infection may be waning, especially in older adults, the original two-shot regimen still offers excellent protection against severe illness and hospitalization in most people.
“It’s unclear that everyone needs to be boosted, other than a subset of the population that clearly would be at high risk for serious disease,” said Dr. Michael G. Kurilla, a committee member and official at the National Institutes of Health.
One key difference between Israel and the United States may explain why the two countries have had different experiences with the vaccine: The countries define severe illness differently.
In Israel, anyone with an accelerated respiratory rate and an oxygen level of below 94 percent is severely ill. By contrast, the C.D.C. reserves that category for people who are sick enough to be hospitalized, said Dr. Sara Oliver, a C.D.C. scientist who presented the American data.
Some committee experts said they also did not feel comfortable offering booster shots to young people who may not need them, when the risks of a third dose are unknown.
The vaccines have been tied to rare cases of myocarditis, inflammation of the heart, in younger people. The risk is very small, and studies have shown that Covid-19 is much more likely to cause the condition.
Last week brought other research in support of the F.D.A. committee’s decision, including one paper by an international team of scientists that analyzed dozens of studies and concluded that the world would be better served by using vaccine doses to protect the billions who remain unvaccinated.
The authors of that study included the top two vaccine experts at the F.D.A., who announced plans to leave the agency this fall. Their departure is in part in protest of the Biden administration’s push for boosters before federal scientists and regulators had reviewed the evidence.
Brazil’s health minister announced that he had tested positive for the coronavirus on Tuesday in New York, where he was attending the United Nations General Assembly along with the country’s defiantly unvaccinated president, Jair Bolsonaro.
The health minister, Marcelo Queiroga, tweeted that he would quarantine in the United States and was “following all health safety protocols.” It was not immediately known whether he was vaccinated.
Mr. Queiroga had accompanied Mr. Bolsonaro during his visit to New York for the U.N. meeting, and was seen on video shaking hands with Britain’s prime minister, Boris Johnson, when Mr. Johnson met Mr. Bolsonaro on Monday.
Mr. Bolsonaro’s handling of the pandemic in South America’s largest country has been widely criticized. He has repeatedly downplayed the threat the virus posed, and his government was slow to secure access to vaccines even as Covid-19 overwhelmed hospitals and killed more than 590,000 people in Brazil.
On Tuesday, Mr. Bolsonaro used his speech at the General Assembly to defend the use of ineffective drugs to treat the coronavirus and argued that doctors should have had more leeway in administering untested medications for Covid-19. The far-right president added that he had been among those who recovered after “off-label” treatment with a malaria drug that studies have found ineffective to treat the disease.
Mr. Bolsonaro, who had a mild case of Covid-19 in July of last year, has said he was in no hurry to get vaccinated, which made for an awkward exchange during his meeting with Mr. Johnson, who hailed the AstraZeneca vaccine, which was developed in Britain at Oxford University.
“Get AstraZeneca vaccines,” Mr. Johnson said. “I’ve had it twice.”
Mr. Bolsonaro pointed to himself and said: “Not yet.”
His unvaccinated status also created hurdles in New York, where restaurants require that patrons show proof of inoculation for indoor seating. On Sunday, one of Mr. Bolsonaro’s ministers posted a photo on Twitter of the president eating pizza while standing on the street alongside several top aides — including Mr. Queiroga.
The Organization for Economic Cooperation and Development said on Tuesday that a global economic recovery from the pandemic was finally taking hold, but it inched back its forecast for worldwide economic growth and warned that the rebound was benefiting wealthier countries more than the developing world as vaccine distribution occurs at an uneven pace.
Countries that have made big strides toward vaccinating most of their populations are bouncing back much more quickly than those that are still struggling to obtain shots, the organization said, raising a host of related economic problems that are affecting global supply chains and pose a risk for the future.
“The global shock that pushed the world to the worst recession in a century is now fading, and we’re now projecting the recovery will bring growth back to its pre-crisis trend,” Laurence Boone, the organization’s chief economist, said in a news briefing.
But vaccination rates remain varied, and many low-income countries and emerging markets, with the exception of China, are still far behind, Ms. Boone added. “A failure to vaccinate globally puts all of us at risk,” she said.
The warnings came as the O.E.C.D. released its semiannual economic forecast, in which it lowered its outlook for global growth, the U.S. economy and emerging markets, but raised its outlook for Europe.
The global growth outlook for 2021 was revised down slightly to 5.7 percent, from 5.8 percent.
Schools have largely reopened this fall, but life is far from normal for parents of young children. One reason is that child care — for children too young for school, and for the hours before and after school — is operating at 88 percent of its prepandemic capacity. Even before the pandemic, child care did not cover everyone who needed it.
The shortage is partly because of the pandemic. Some centers went out of business after lockdowns early on. Because children under 12 are not yet eligible for vaccines, many programs are enrolling fewer children to limit potential exposure.
But the biggest reason for the shortages, child care providers across the country said, is that they can’t find people to hire.
Eight in 10 providers said they were experiencing a staffing problem, and half said hiring was harder than before the pandemic, according to a survey over the summer of 7,500 of them by the National Association for the Education of Young Children.
Half said they were serving fewer children as a result of hiring problems, and a quarter had reduced their hours. The lack of child care is also contributing to other labor shortages, because many parents who can’t find reliable child care can’t return to work.
Child care providers face challenges like those in many other service industries that are unable to find enough workers: low pay and little job stability. The median hourly pay is $12, and 98 percent of occupations pay more, according to data from the Center for the Study of Child Care Employment at the University of California, Berkeley.
Turnover is high in early childhood education, and jobs caring for school-aged children are only a few hours a day and often end in the summer.
Child care has additional challenges. Some people are hesitant to work with unvaccinated children. The job requires more qualifications, including background checks, certifications and even college degrees in some areas, than the stores and restaurants that are paying more.
Yet child care centers have not responded the way some other industries have — by significantly raising wages and expanding benefits.
