FDA supports third dose for older and high-risk populations

Booster for Some

Amid much anticipation, advisers to the Food and Drug Administration (FDA) unanimously supported giving a third dose of Pfizer's coronavirus vaccine to older adults or those who are at high risk of severe COVID-19 while overwhelmingly opposing the rollout of booster shots more broadly to people older than 16. The results of the September 17 meeting dealt a blow to an ambitious plan announced by the Biden administration last month.

While the FDA is not required to follow its advisers' recommendations, it usually does, according to BioPharma Dive. A decision from the FDA is expected in the coming days.

The panel was originally asked by the agency whether an additional dose of the companies' vaccine should be approved for anyone 16 or over. Advisers were overwhelmingly opposed, with all but two voting against the proposed recommendation.

Then, the FDA's top vaccine reviewers drafted a new proposal for booster shots six months after the first set of vaccinations in adults over 65 or who are at higher risk of worse outcomes from infection — groups the advisers judged most likely to benefit from an additional dose based on current evidence gathered.

According to Michael Kurilla, a committee member, "I think we need to target the boosters right now, but specifically to the people who are likely to be at high risk, and it's an older population, it's immunocompromised." In August the FDA authorized booster doses of both Pfizer's and Moderna's vaccines for immunocompromised individuals.

The committee recommended an emergency authorization of a third Pfizer shot, rather than an approval as the drugmaker had requested. Members of the panel also gave the green light to a third shot for healthcare workers or others whose jobs put them at higher risk of exposure. While the committee did not address the issue of additional doses for people who received either Moderna's or Johnson & Johnson's vaccine, its recommendation could influence how the FDA handles other authorizations.

The FDA called Friday's meeting in response to Pfizer’s request for authorization of a booster dose of its vaccine in people aged 16 years and older. Pfizer based its case on immune response data collected from people given a third dose in an early clinical trial and from 300 participants in the Phase 3 study that led to the vaccine's initial authorization and approval. Those results indicated that an additional dose, administered months after the first two, greatly raised levels of neutralizing antibodies against the coronavirus and appeared safe. Side effects were similar to those that occurred after the second dose.

Pfizer also used data from studies of real-world use compiled by researchers in Israel and by Kaiser Permanente, indicating diminished protection against infection. Advisers heard from Israeli health officials, who said that had the country not begun giving its citizens a third dose at the end of July, hospitalizations would have risen higher during the fourth wave Israel is now experiencing.

Dr. Sharon Elroy-Preiss, director of public health services at Israel's Ministry of Health, explained that Israel had started to see a "trend of severe, critically-ill patients" ranging from ages 40 to 60 who had only received two doses. She added, "We didn't want to wait to see those results and we knew that we needed to vaccinate a larger portion of the population in order to get the numbers down quickly."

Advisers were concerned about recommending booster shots more broadly because of the possible risk of inflammation in and around the heart. The CDC is now compiling safety data on the 1 million Americans who received a third dose and plans to have that ready shortly.