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The Food and Drug Administration on Wednesday granted an emergency use authorization to Pfizer and BioNTech’s Covid-19 vaccine booster, though for now the FDA said use of the booster should be restricted to people over the age of 65, adults 18 and older at high risk of severe Covid, and those who, like health care workers, are at higher risk of infection because of their jobs. That list includes teachers.

With the agency’s ruling, the Biden administration is one step closer to implementing its plan to begin to offer booster shots to Americans, a campaign it had announced would begin this week. At this point, however, only boosters using the Pfizer vaccine can be considered.

“This pandemic is dynamic and evolving, with new data about vaccine safety and effectiveness becoming available every day,” Acting FDA Commissioner Janet Woodcock said in a statement announcing the authorization. “As we learn more about the safety and effectiveness of COVID-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed.”


While the FDA’s ruling means boosters will not currently be available to as broad a population as the Biden administration had hoped, the groups indicated could encompass a large proportion of the adult American population.

The CDC estimates that there are roughly 53 million Americans aged 65 and older. Another 17 million to 20 million people are health care workers. And as many as 100 million people are estimated to have medical conditions that put them at increased risk of severe illness if they contract Covid.


The FDA’s statement said a broad array of essential workers — “health care professionals, teachers and day care staff, grocery workers and those in homeless shelters or prisons, among others” — should be eligible for boosters.

One group that did not make the cut was 16 and 17 year olds. Pfizer had applied for the booster for everyone 16 years of age and up, but did not provide any data to support the safety of a third shot in anyone under 18. The FDA’s advisory committee objected strenuously to their inclusion and the authorization for the booster is for people 18 and older.

Pfizer and BioNTech had requested a full license for their booster shot, which they hoped would be made available to anyone who had previously received their vaccine. They proposed the third shot be given at least six months after the second jab in the series.

But in a rigorous meeting last Friday, the expert panel that advises the FDA on vaccines voted against recommending that broad use, with members arguing there isn’t enough evidence to support the contention that everyone 16 and older who received the Pfizer vaccine needs to be boosted six months after their second shot. While the FDA isn’t bound to follow the advice of the Vaccines and Related Biological Products Advisory Committee — known as VRBPAC for short — it generally does. And it has, more or less, in this situation.

The committee voted 16 to 2 against boosters for all at this point. But it voted 18 to 0 in favor when asked if the evidence supports giving a third dose to people over the age of 65 and to people at high risk of developing severe Covid, if they contract the disease. The question did not stipulate who qualified as high risk, though there was discussion about people who are frequently exposed to Covid, like health care and front-line workers, and people with medical conditions like obesity and diabetes that have been linked to a higher risk of serious disease.

Fine-tuning who should be offered Pfizer booster doses at this time will now fall to the Centers for Disease Control and Prevention’s vaccine expert panel, the Advisory Committee on Immunization Practices. It will vote on Thursday about whether to advise the CDC to recommend use of the booster jab, and which groups of people should be offered it at this point. CDC Director Rochelle Walensky will then have to sign off on ACIP’s recommendations. Like the FDA and its vaccines advisory committee, the CDC director is not obligated to follow ACIP’s advice, but almost always does.

The group met all day Wednesday to discuss Covid vaccine efficacy data and the evidence for waning of protection, among other issues. The meeting flagged issues the ACIP will likely find challenging when they debate booster recommendations on Thursday, including the fact that some of the people who may need a booster jab soon were not initially vaccinated with the Pfizer vaccine. Boosters for the Moderna and the Johnson and Johnson vaccine have not yet been authorized.

Several ACIP members asked if they would be able to recommend that people who qualify for a booster could get the Pfizer jab regardless of which vaccine they initially received. Another wondered if it made sense to hold off beginning the booster shot campaign until all three boosters have been authorized by the FDA.

“I don’t want to jeopardize anyone,” said Sarah Long, a professor of pediatrics at Drexel University College of Medicine. “At the same time, it will be very, very difficult to have a little less than half of the population who are eligible [for a booster] to be able to receive one.”

Molly Howell, a non-voting member of the committee who represents the Association of Immunization Managers, warned that having a booster from only one of the companies supplying vaccine to the United States would create real logistical problems, especially when it comes to delivering booster shots to residents of nursing homes.

“In North Dakota, when we looked at our long-term care facilities, the vast majority had a mixture of people who needed Moderna and Pfizer,” said Howell, who is also the immunization program manager for the North Dakota department of health. “I don’t know if it’s realistic to keep going back with different brands.”

Howell noted that when the ACIP voted to recommend that people who are immunocompromised should be given a third dose, the committee said that if the vaccine brand an individual had received for dose 1 and dose 2 wasn’t available, they could be vaccinated with another product. “I think that would be very helpful, especially when we’re talking about vaccinating in a long-term care setting.”

Doran Fink, from the FDA’s Office of Vaccines Research and Review, said the agency doesn’t currently have enough data to tell it that getting a booster dose with a different vaccine would be as effective at getting a third dose of the same vaccine.

“I do really appreciate the concerns around flexibility and around timing of availability of other authorized vaccines for a booster dose,” Fink said, suggesting he would consult with FDA colleagues and come back with an answer on Thursday.

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