FDA panel backs half-dose Moderna booster for the elderly and others at high risk

Moderna manufacturing site
An FDA panel recommended a half-dose of the Moderna COVID-19 vaccine for use as a booster shot. Mirroring the FDA’s authorization of Pfizer-BioNTech boosters, the Moderna backing covers people 65 and older and others at high risk. (Moderna)

An FDA advisory committee voted unanimously Thursday to recommend Moderna's COVID-19 vaccine as a booster for people 65 and older and others at high risk.

The Vaccines and Related Biological Products Advisory Committee backed emergency authorization for booster doses at least six months after completion of the original two-shot Moderna series.

The booster won't be identical to the first two shots, though. The committee signed off on Moderna’s plan for a 50-microgram, or half-dose, for the booster compared to the 100-microgram dose used in the original two-shot series.

The FDA will now weigh and refine the recommendation, with a decision likely to come next week.

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The committee's backing mirrors the FDA’s emergency authorization of the Pfizer-BioNTech vaccine booster. Last month, that shot won a nod for people 65 and older and others 18 and older with disorders that leave them at risk of developing complications or with occupations that put them at risk of exposure to the virus.

Friday, the panel will meet again to discuss Johnson & Johnson’s request for approval of its COVID-19 vaccine.

Before endorsing use of the Moderna booster, panel members noted several concerns about extending booster shots beyond the limited population group, including the scant data available, the myocarditis risk to young males and the unknowns surrounding long COVID in children and whether boosters help populations achieve herd immunity.

“We’re asked to consider these questions without regard often to whether recommending something would become making it available to a particular age group versus it turning into a mandate,” said Ofer Levy, M.D., Ph.D., of Boston Children’s Hospital. “That’s not really the purview of our committee.”

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Answers to the questions the committee posed Thursday will become readily available over time as more data on the shot accumulate. Panelists largely agreed that it was premature to recommend for a more sweeping approval.

“I think we heard pretty loud and clearly that there is not a lot of appetite for moving down the age range very significantly,” said Peter Marks, M.D., the director of the Center for Biologics Evaluation and Research. “We do hear very loud and clear the need for benefit/risk considerations. It is a very challenging pandemic. The problem here is we don’t know what we don’t know.”