US FDA asks Covid-19 vaccine makers to target KP.2 strain, if feasible, for next shot

WASHINGTON – 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 (FDA) change in recommendation, in an update dated June 13, comes even as Moderna and Novavax – makers of two of the three Covid-19 vaccines – submitted their applications to the agency for updating the autumn 2024 season shots with the JN.1 strain.

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

The company applied for authorisation on June 14 and said its shot showed broad cross-neutralising 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 Organisation, all of which sought targeting the JN.1 strain with the updated vaccines.

The FDA’s Peter Marks, during the advisory panel’s meeting earlier in June, 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 are paying an incredibly high premium for mRNA vaccines to be able to have the freshest vaccines,” Dr Marks, director of the FDA’s Centre for Biologics Evaluation and Research, had said then.

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

JN.1 was the dominant strain in the US earlier in 2024.

While it is no longer as prevalent, it is estimated to account for 3.1 per cent of cases over a two-week period ended June 8, the Centres for Disease Control and Prevention data showed.

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

Pfizer said on June 14 that 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 autumn vaccination campaign, regardless of the final decision on the strain.

REUTERS