FDA Panel Votes Against Recommending Pfizer COVID-19 Booster Doses for General Public

An FDA advisory committee has rejected Pfizer and BioNTech’s plan to deliver COVID-19 booster shots for individuals 16 years of age and older, saying they need more data.

The panel did, however, vote to recommend the booster shots to adults over 65 years of age and those at high risk of severe COVID-19, according to reporting by the Washington Post. The booster shots would be given at least 6 months after the primary doses.

The committee vote comes days before the Biden Administration planned to begin releasing booster shots to the general public. Although the panel’s decision is nonbinding, it could strongly influence the final FDA decision expected soon.

Pfizer and BioNTech initiated rolling submission of the Biologics License Application for booster doses in individuals 16 years of age and older in late August, citing phase 3 data that a third dose induces significant neutralizing antibody titers. According to a press release, SARS-CoV-2 neutralizing titers against the wild-type strain 1 month after the booster dose was administered were 3.3 times higher than the titers found 1 month after the second dose.

These findings are from a phase 3 trial with 306 participants between the 18 and 55 years of age who received a third dose of the vaccine between 4.8 months and 8 months after the primary 2-dose regimen. Researchers had a median follow-up time of 2.6 months post-booster and the neutralizing titers after the third dose met a prespecified 1.5-fold non-inferiority criterion of success and were statistically superior. Notably, 99.5% of participants had a 4-fold response following the third dose, compared to 98% of participants after the second dose.

The trial also had a favorable reactogenicity profile within 7 days after the booster dose, with mostly mild to moderate reactions. The most common adverse events included injection site pain, fatigue, headache, muscle and joint pain, and chills. The frequency of reactogenicity was similar to or better than after dose 2 of the primary series.

Despite these findings, experts expected the advisory panel decision to be controversial. According to reporting by CNBC, 2 senior FDA officials involved in the meeting have said they are not convinced that every American who has received the Pfizer vaccine needs extra doses right now.1

In a paper published earlier this week in The Lancet, experts from the FDA and World Health Organization said that according to current data, COVID-19 vaccines continue to be effective in protecting against severe SARS-CoV-2, including disease caused by the Delta variant. They added, however, that boosters could be appropriate for some individuals who may not have received adequate protection from the primary series, such as immunocompromised individuals.2

“Although the benefits of primary COVID-19 vaccination clearly outweigh the risks, there could be risks if boosters are widely introduced too soon, or too frequently, especially with vaccines that can have immune-mediated side effects,” the authors wrote. “If unnecessary boosting causes significant adverse reactions, there could be implications for vaccine acceptance that go beyond COVID-19 vaccines.”2

According to CNBC, some FDA committee members argued that booster doses should be limited to certain groups, such as individuals 60 years of age and older who are at a greater risk of severe disease. Some members specifically expressed concerns about the risk of myocarditis in younger people and said that more research is needed.

REFERENCES

1. FDA panel rejects plan to administer Pfizer’s Covid booster doses to general public. CNBC; September 17, 2021. Accessed September 17, 2021. https://www.cnbc.com/2021/09/17/fda-panel-begins-voting-on-pfizers-covid-booster-doses-rejecting-shots-for-general-public.html

2. Krause P, Fleming T, Peto R, et al. Considerations in boosting COVID-19 vaccine immune responses. The Lancet. September 13, 2021. Accessed September 17, 2021. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02046-8/fulltext