By Puyaan Singh and Christy Santhosh

May 22 (Reuters) - U.S. Food and Drug Administration

advisers unanimously recommended on Thursday that COVID-19

vaccines for the 2025-26 period should target newer strains of

the JN.1 variant.

COVID vaccine makers are seeing increased regulatory

scrutiny under the new FDA leadership, facing tighter

requirements for their shots that could increase expenses.

FDA Commissioner Martin Makary and top vaccines

regulator Vinay Prasad have both been critical of current U.S.

COVID vaccine policies and have indicated that they were under

review.

The panel's discussion on Thursday touched upon the

prevalence of various strains. Government data indicate that the

LP.8.1 strain - a subvariant of the previously recommended JN.1

strain - accounts for about 70% of total cases in the United

States.

"We cannot predict the future very far out, but it does seem

like (targeting) LP.8.1 is likely to provide us better

coverage," said panelist Eric Rubin, adjunct professor at

Harvard T.H. Chan School of Public Health.

Shares of vaccine makers Novavax ( NVAX ) closed 2.5%

higher, Moderna ( MRNA ) 3.6% higher, while those of Pfizer ( PFE )

closed nearly flat.

The advisory panel also emphasized the need for frequent

reviews, given that the dominant strain could change again.

"This virus is still continuing to mutate ... It might be

worthwhile to take another look [at vaccine composition] ...

particularly for those for whom we are already recommending two

doses during the year," said Archana Chatterjee, dean of Chicago

Medical School.

However, the committee cautioned that updating vaccines more

than once a year would be unfair to manufacturers.

Novavax ( NVAX ) said on Thursday it was prepared to manufacture an

updated vaccine in time for the vaccination season.

Pfizer ( PFE ) and its partner BioNTech expect to supply

the vaccine immediately upon approval, while Moderna ( MRNA ) hopes to

launch it by mid-August.

Based on the panel's discussion, the FDA will soon decide

which strain the vaccine makers should target.