By Denise Baez
The US Food and Drug Administration’s (FDA) Vaccines and Related Biological Products Advisory Committee voted against giving a third dose, or a booster dose, of Pfizer’s coronavirus disease 2019 (COVID-19) mRNA vaccine (BNT162b2) in individuals aged 16 years and older.
Of the 18 members of the voting committee, 16 voted against booster vaccines at this time, based on the current available data, for individuals aged 16 years and older.
However, the committee voted unanimously on a second question: whether the potential benefits outweigh the known and potential risks of the BNT162b2 vaccine booster dose administered at least 6 months after completion of the primary series for use in individuals aged 65 years and older, and among individuals at high risk of severe COVID-19. The committee believes that an Emergency Use Authorisation (EUA) for booster shots for these 2 groups is warranted. Those considered at high risk for severe COVID-19 include individuals with high exposure to the virus, including healthcare workers and emergency responders.
The deliberation came after an almost 7-hour meeting where data from Israel’s Ministry of Health and Pfizer were presented. Israel has already rolled-out a booster vaccination program and presented data from a very small cohort of about 300 individuals who have received a third vaccine dose.
“We don’t have the same data, or the same context of data that is in Israel, here in the United States,” said Advisory Committee Member Ovetta Fuller, PhD, University of Michigan, Ann Arbor, Michigan. “I’m not comfortable with only 300 or so people as an end[point] for the booster in the clinical phase 3 safety study that we’re asked to evaluate. I would like us to feel much more comfortable with what we’re looking at from this clinical study in the United States, with the differences that we have in our population. There’s too many questions for me to say yes to this without more details from a clinical study.”
Concerns regarding approval or recommendation of a booster vaccine dose for the general public at the current time included the fact that clinical trials on the safety and effectiveness from the first 2 doses are not yet complete. Global equity was another factor, with many expressing that the priority should be vaccinating as many people as possible with at least 2 doses of a COVID-19 vaccine before booster shots are even considered. Also, in light of the increase in cases of myocarditis and thrombotic thrombocytopenia following receipt of a COVID-19 vaccine, especially in younger recipients, it is unclear whether a third dose might exacerbate these cases. There was also discussion as to why there continues to be a high number of daily COVID-19 cases in Israel -- a country with a very high vaccination rate -- even with a booster vaccine rollout. It is not known for how long vaccines offer protection, but some studies have shown that protection wanes after about 6 months.
Although the committees provide recommendations to the FDA, final decisions are made by FDA, and may or may not take into consideration the committee’s recommendations.