A day after federal regulators authorized Pfizer-BioNTech coronavirus booster shots for Americans at risk of severe COVID-19, scientific advisers to the Centers for Disease Control and Prevention on Thursday recommended the booster shots for a wide swath of the country, including tens of millions of older Americans and those with certain medical conditions. But the panel excluded those at risk because of their jobs.
The Food and Drug Administration on Wednesday authorized boosters for older and high-risk recipients of the Pfizer vaccine at least six months after their second injection, as well as for people whose jobs leave them exposed to the virus, including health workers, teachers and grocery workers.
The CDC’s science advisers unanimously supported the booster for adults older than 65 and for residents of long-term care facilities. And 13 of the committee’s 15 members also endorsed the shots for people ages 50 to 64 with medical conditions that leave them at risk for severe COVID-19.
Some members urged the committee to include some flexibility for individuals under 50 to obtain boosters, based on their individual benefit and risk. But others pointed — with considerable frustration — to a lack of data supporting the need in the other groups.
After a protracted discussion, a majority of the panel recommended the boosters for adults ages 18 to 49 with underlying medical conditions, based on their individual benefit and risk.
They disagreed most on whether some people in some occupations or settings are at heightened risk. By a close vote of 9-6, they voted to exclude people at risk because of their occupations. This measure would have applied to health care workers, teachers and other workers who do not meet the other criteria.
The Pfizer-BioNTech vaccine is approved for anyone over age 16, but the FDA’s authorization for the booster includes only those over age 18.
Dr. Rochelle Walensky, the CDC director, is expected to endorse the recommendations of its scientific advisers Thursday or Friday, and people who meet the criteria could start getting the shots immediately afterward.
The number of Americans who will qualify includes only those who already received two doses of the Pfizer-BioNTech vaccine. The panel was not asked to judge whether people who received the Moderna and Johnson & Johnson vaccines should receive booster shots, which have not been authorized by the FDA.
Several experts nevertheless supported a mix-and-match strategy, and signaled that they would revisit the issue as new data emerge.
State health departments generally follow the recommendations of the CDC’s Advisory Committee on Immunization Practices.
And anyone who wants a booster may simply be able to walk into a pharmacy and ask for one — many Americans already did so before the FDA’s authorization, typically by finding a cooperative pharmacist or pretending to be unvaccinated.
The CDC panel’s guidance followed weeks of internal disagreement and public debate among American health officials and advisers. In mid-August, President Joe Biden announced plans for a booster rollout, but regulators significantly slowed the proposed timeline.
And public health experts criticized what they said were confusing public messages from the Biden administration, all the more notable because the FDA does not have a permanent leader. Its acting commissioner, Janet Woodcock, said Wednesday that the authorization would allow for booster doses “in certain populations such as health care workers, teachers and day care staff, grocery workers and those in homeless shelters or prisons, among others.”
But some members of the CDC panel said there was little evidence to suggest that vaccinated teachers, and even health care workers, are at risk of repeated exposure to the virus.
Millions of Americans who received the Moderna and Johnson & Johnson vaccines are still waiting to learn whether they, too, can get boosters. The FDA is expected to take up the question in short order.
During a two-day meeting culminating Thursday, the CDC’s advisory panel wrestled with the public’s expectations for COVID vaccines, the safety of third doses and how a booster program would affect nursing home residents.
The advisers also grappled with the lack of clarity on the goal of the vaccines: Is it to prevent all infections, or only to forestall severe illness and hospitalization? Many suggested it should be the latter, and that thwarting all infections was a foolhardy goal.
Several members of the committee pointedly questioned why federal health agencies were focusing on booster shots for Pfizer recipients to begin with, given the higher risks facing the unvaccinated.
“We may move the needle a little bit by giving a booster dose to people,” said Dr. Helen Talbot, an associate professor of medicine at Vanderbilt University. But, she added, “the hospitals are full because people are not vaccinated.”
Pfizer scientists had argued to the committee that waning antibody levels in people who had received the shot indicated that their immunity was dropping.
And on Thursday, CDC scientists presented models indicating that, if booster doses were to slightly increase people’s protection against hospitalization, the additional shots could prevent more than 2,000 hospitalizations for every 1 million doses given.
But it is not at all clear how long any additional protection from a booster would last.
Some committee members doubted the wisdom of looking only at antibody levels to gauge immunity. The antibodies needed to prevent infection may naturally wane a few weeks to months after the injection, but the immune cells that prevent illness from progressing — but are harder to measure — remain stable many months after the second dose, according to data presented by one CDC scientist.
Boosters can reduce infections in nursing home residents, who are among those at highest risk. Even so, cases in nursing homes will persist when community transmission is high, according to a modeling study presented at the meeting.
Scientists who presented data to the advisers noted that while a third dose would undoubtedly amp up antibody levels, it’s unclear how long those elevated levels would last, whether they translate to meaningful extra protection against severe disease, and whether they can significantly decrease transmission of the virus.
They also noted the paucity of safety data, especially among younger people.
The advisers also wrestled with the practicalities of endorsing a booster shot of Pfizer’s vaccine, but not of Moderna or Johnson & Johnson’s. Recipients of those vaccines may rightly feel resentful of being asked to wait if the evidence suggests they need boosters, they noted.
“I just don’t understand how, later this afternoon, we can say to people 65 and older, ‘You’re at risk for severe disease and death, but only half of you can protect yourselves right now,’” said Dr. Sarah Long, a pediatrician and infectious diseases expert at Drexel University College of Medicine in Pennsylvania.
“It might be the right thing to do,” she said. “It just doesn’t sound like a good public health policy.”
Some experts seemed to suggest Wednesday that it might be better to hold off on recommending any booster shots until recipients of all three vaccines could qualify for them.
Moderna’s authorization may arrive in a few days to weeks. The company has applied for authorization of a booster carrying half the dosage given in the first two shots, which has delayed the FDA’s deliberations.
Federal regulators have indicated that there was insufficient evidence for mixing first shots of the Moderna vaccine with a Pfizer booster, or vice versa.
Some global health experts have criticized the Biden administration for pushing booster shots when much of the world has yet to receive a first dose. But analysts also noted that even if the United States gives booster shots, there would be considerable excess vaccine supply this year, and urged the government to begin sending those doses abroad.