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FDA advisers back updating COVID shots to target JN.1 virus family

A group of advisers to the Food and Drug Administration on Wednesday unanimously recommended that COVID-19 vaccines be updated to cover coronavirus strains with a family known as JN.1 ahead of the fall.

The committee, which had originally been scheduled to meet in mid-May, supported targeting the JN.1 lineage broadly, rather than some specific subvariants that are now more prevalent in the U.S. Their recommendation matches the advice of the World Health Organization, which in April also recommended COVID shots cover the JN.1 family.

According to documents prepared by FDA staff, a JN.1 offshoot known as KP.2 has been the dominant variant in the U.S. since April. Both the broader lineage and KP.2 are distinct from the XBB virus variants that vaccines currently target.

Committee members argued that aiming vaccines at JN.1 would be effective, although some did express concern the unpredictability of viral evolution could blunt the potency of an updated shot.

“Having a vaccine that [covers] part of the trunk of the tree rather than the branches makes sense to me,” said Melinda Wharton, a panel member and associate director for vaccine policy at the National Center for Immunization and Respiratory Diseases. “I think the chances of having broad cross-protection are probably greater, and I am concerned about not potentially having all the vaccine platforms available.”

At the meeting, Pfizer, Moderna and Novavax each presented animal model data, and said they could make updated formulations of their shots available in time for fall vaccination campaigns. Novavax’s vaccine, which unlike Pfizer’s and Moderna’s messenger RNA shots is protein-based, takes longer to adapt and manufacture, however.

Several panelists felt that having a third option was important for people who may be hesitant to receive an mRNA shot — a view that was shared by Peter Marks, head of the FDA office that reviews vaccines.

“As I understood the comment from Novavax, if the KP.2 strain was selected, they would not necessarily deliver the vaccine on time,” said Mark Sawyer, a committee member and professor of clinical pediatrics at the University of California, San Diego. “And I think that at this point is a major problem … [the vaccine] needs to be equitably available to everybody at the same time.”

The agency isn’t required to follow the advice of its committees, but it usually does.

The committee has met annually since 2022 to discuss COVID shot composition, a pattern similar to how updates to influenza vaccines are handled. COVID cases haven’t always tracked as closely with the change in seasons as do those for flu or respiratory syncytial virus, though.

Ruth Link-Gelles, an epidemiologist with the Centers for Disease Control and Prevention, said an upcoming CDC panel could consider whether individuals might need an additional shot if they received one before a peak in cases.