FDA outlines stricter Covid vaccine booster approval standards for healthy people

The Food and Drug Administration on Tuesday outlined new regulatory guidance for future Covid-19 vaccine boosters, setting stricter approval standards for healthy Americans. 

The FDA recommended different standards of evidence for approval based on patients' risk of getting severely sick from Covid, according to a paper published Tuesday in the New England Journal of Medicine. The paper's authors are FDA Commissioner Marty Makary and Vinay Prasad, an outspoken critic of the pharmaceutical industry who was appointed to lead the agency's division that oversees vaccines.

The new guidance comes as Health and Human Services Secretary Robert F. Kennedy Jr., a prominent vaccine skeptic, overhauls the nation's health agencies.

For adults 65 and older, and for people as young as 6 months who have certain underlying health conditions, the FDA said it will accept immunogenicity data – which shows a vaccine triggers a strong enough antibody response – as enough to determine that a shot's benefits outweigh its risks.

But for healthy people between 6 months and 64 years old who don't have risk factors, the agency plans to require stronger evidence for vaccines from randomized, controlled trials. These studies must show actual clinical outcomes, such as fewer infections or hospitalizations, before the FDA grants full approval of a shot. 

When approving a Covid vaccine for high-risk people, the FDA will encourage manufacturers to conduct randomized, controlled clinical trials in healthy adults as part of their post-marketing commitment for the shot.

Previously, the FDA relied more heavily on immunogenicity data when evaluating Covid booster shots – which are tailored to new circulating strains of the virus – for approval for all Americans each year. That approach mirrored the flu vaccine model, where annual strain updates are approved based on immune response data, not full clinical trials.

"The FDA's new Covid-19 philosophy represents a balance of regulatory flexibility and a commitment to gold-standard science," the agency said in the paper.  "The FDA will approve vaccines for high-risk persons and, at the same time, demand robust, gold-standard data on persons at low risk."

Makary and Prasad will address the new framework during a virtual town hall on Tuesday at 1 p.m. ET.