FDA panel recommends updating the Covid vaccines for the fall to target JN.1 strain

FDA panel recommends updating the Covid vaccines for the fall to target JN.1 strain

An offshoot of JN.1 is now the dominant strain in the U.S., accounting for 1 in 4 new cases.

A Pfizer COVID-19 vaccine booster shot being administered in person’s arm as the Mount Sinai South Nassau Vaxmobile vists Freeport High School, in Freeport, New York

The FDA is expected to make a final decision soon on which strain it will advise drugmakers to target.Steve Pfost / Newsday via Getty Images file

June 6, 2024, 1:42 AM GMT+5:30

By Berkeley Lovelace Jr.

Although Covid cases remain low in the U.S., vaccine experts are already looking toward the winter, with eyes on preventing a seasonal surge.

A Food and Drug Administration advisory panel on Wednesday unanimously recommended that the Covid vaccines for the fall be updated to target the highly contagious JN.1 variant or one of its descendants.

JN.1 emerged in the U.S. in late August and by January became the dominant strain in circulation.

Various offshoots of JN.1 soon followed, including the so-called FLiRT variants, KP.1.1 and KP.2. In mid-May, KP.2 overtook JN.1 as the dominant strain in the U.S., and it now accounts for over 1 in 4 new cases, according to the Centers for Disease Control and Prevention.

Natalie Thornburg, a research microbiologist at the CDC, said at Wednesday’s meeting that the coronavirus appears to be adopting a consistent pattern: a dominant “parent” strain takes hold in early winter, and by spring, a handful of descendants emerge. That’s also what happened with the XBB strain last year, she said, which dominated in the winter but gave rise to offshoots in the spring.

The panel’s recommendation didn’t specify whether to include the “parent” JN.1 strain or one of its descendants, but most panel members expressed a preference for JN.1.

“The trunk of the tree is probably our best bet for now,” said panel member Dr. Bruce Gellin, the chief of global public health strategy at the Rockefeller Foundation, in a discussion following the vote.

Dr. Peter Marks, the FDA’s top vaccine regulator, urged the committee to consider one of the more recent strains, such as KP.2.

“We are paying an incredibly high premium for mRNA vaccines to be able to have the freshest vaccines,” Marks said, a reference to the speed with which new mRNA-based vaccine shots can be developed and produced.