FDA panel mulls over Covid booster issues despite 'insufficient data'

The following is an excerpt from MedPage.

All the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) could agree about on Wednesday in terms of a plan for Covid boosters is that they need more data.

FDA staff charged VRBPAC members with discussing what considerations should inform strain composition decisions for Covid boosters, how often should these be assessed, what would indicate a need for an updated strain composition, and what considerations should inform timing and populations for Covid boosters.

Members agreed that the focus of boosters should be preventing hospitalization and death, but they didn't feel comfortable with boosters every 8 weeks. They also seemed to settle on 80% protection from severe outcomes as an acceptable threshold for vaccine effectiveness.

But questions about which data should inform booster selection, and timing of vaccination were more gray areas

"If we're going to do this in a timely fashion, we're going to have to use safety and immunogenicity as our endpoints and not clinical data," said Rubin, who is also editor-in-chief of the New England Journal of Medicine. "I just don't think it's going to be practical."

VRBPAC members also lamented the lack of concrete correlates of protection. FDA's Peter Marks, MD, PhD, director of the Center for Biologics Evaluation and Research, said that the agency is "working with NIH colleagues, trying to work through this."

Though VRBPAC members agreed that in an ideal world, they would like to see clinical data to inform decisions on boosters, Eric Rubin, MD, PhD, of Brigham and Women's Hospital in Boston, questioned if the timing for manufacturing would make that feasible.

Marks indicated that FDA would need to decide by June if current vaccines were to be updated to target different strains for a fall booster. (Continued...)

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