COVID-19 booster gets FDA panel backing for 65 and up; blanket use shot down

Advisers to the US FDA* unanimously voted for emergency use authorization (EUA) of the Pfizer/BioNTech COVID-19 vaccine booster dose in people 65 years and older and those at high risk of severe COVID-19.

The Vaccines and Related Biological Products Advisory Committee (VRBPAC) of the FDA voted 18-0 recently, giving weight to the known benefits of a booster shot vs potential risks for older adults and those 16 years and older at high risk of severe disease. That has previously included people with diabetes, heart disease, obesity, and other comorbidities.

The VRBPAC also recommended that healthcare workers and other individuals at high risk for occupational exposure such as teachers be included in the EUA.

Pfizer had originally proposed a booster shot for all individuals 16 years and older.  However, the committee shot down the full approval bid by a vote of 16-2, citing a lack of safety data for broad use in the general population and the risk of myocarditis in younger men.

The FDA will have to decide soon whether it would adopt or overrule the advisers’ recommendations.

Good evidence on hand

Primary support for the booster comes from the early safety and immunogenicity data from the phase I/II/III Pfizer studies, involving a cohort of 300 adults 18 years and older who received booster doses, including 12 individuals 65 years and older. [https://clinicaltrials.gov/ct2/show/NCT04368728]

Published real-world data from Israel also showed a benefit for a booster dose in those 60 years and older who had received two doses of the Pfizer vaccine at least 5 months earlier. [N Engl J Med 2021;doi:10.1056/NEJMoa2114255]

However, the committee did not buy the justification of waning vaccine efficacy as the significant driver of transmissions in the US. More weight was given instead to the US Centers for Disease Control and Prevention (CDC) report that the spike in cases was more pronounced in unvaccinated groups.

The advisers also wanted more data on the circulating variant, studies of longer time between primary series, and a longer follow-up after the booster dose to determine if immunity is durable.

One of the two advisers who voted for the full approval, Dr Mark Sawyer from the University of California San Diego in California, US, argued that a full approval would be the quickest and most efficient way for providers to target high-risk populations in need of booster shots.

Meanwhile, the CDC is currently evaluating data on the 1 million individuals who received a third dose of the vaccine. Results are expected to be out soon.

The earlier the better

US National Institute of Allergy and Infectious Disease director Dr Anthony Fauci, who is a known backer of boosters, has gotten ahead of the FDA and CDC in supporting COVID-19 booster doses, believing that the earlier the booster dose is approved, the better. “There’s very little doubt that the boosters will be beneficial,” he said.

His group had conducted experiments as early as March 2021, reviewing early data from humans and demonstrating that COVID-19 booster shots induced protective antibodies even against new variants of concern.