US asks COVID vaccine makers to target KP.2 strain

The US health regulator has changed its strain recommendation for the 2024-25 COVID-19 vaccines, as it asked manufacturers to update the new shots to target the KP.2 variant, if feasible, instead of the JN.1 lineage it sought to target earlier.

The Food and Drug Administration’s change in recommendation, in an update dated Thursday, comes even as Moderna and Novavax — makers of two of the three COVID vaccines — submitted their applications to the agency for updating the fall 2024 season shots with the JN.1 strain.

Novavax had said its manufacturing is underway for a JN.1 vaccine and it cannot have a shot this fall for another strain.

The company applied for authorization on Friday and said its shot showed broad cross-neutralizing antibodies against multiple variants, including KP.2 and KP.3. It said it can be ready with its JN.1 shot by mid-July.

Novavax was not immediately available for comment on the FDA’s preference for a KP.2 shot.

The FDA’s new advisory differs from recommendations of its own advisers and the European regulator and World Health Organization, all of which sought targeting the JN.1 strain with the updated vaccines.

However, FDA’s Peter Marks, during the advisory panel’s meeting earlier this month, had said he wanted to give people the choice of a KP.2-targeting vaccine, counting on the quick updates possible with messenger RNA shots from Moderna and Pfizer and its partner BioNTech.

“We always say we shouldn’t be chasing strains, but we’re paying an incredibly high premium for mRNA vaccines to be able to have the freshest vaccines,” Marks, director of the FDA’s Center for Biologics Evaluation and Research, had then said.

mRNA vaccines can be developed more quickly than Novavax’s protein-based shot.

JN.1 was the dominant strain in the U.S. earlier this year. While it is no longer as prevalent, it is estimated to account for 3.1% of cases over a two-week period ended June 8, the Centers for Disease Control and Prevention data showed.

The KP.2 variant was estimated to account for about 22.5% of cases, with KP.3 now becoming dominant at 25%.

Pfizer said on Friday it was having discussions with regulators globally, including the FDA, to assess the composition of future COVID vaccine formulations. Moderna said it would be ready with the updated shot in time for the fall vaccination campaign, regardless of the final decision on the strain.

Shares of Novavax, Moderna and BioNTech each closed more than 3.5% down in the U.S.