Advisers to the U.S. Food and Drug Administration will discuss recommendations for updated COVID-19 vaccines ahead of the upcoming immunization campaign, including if these shots should target the LP.8.1 subvariant, documents filed on Tuesday showed.

The documents, posted ahead of the advisers’ meeting on Thursday, said a discussion regarding the targeted strain for the 2025-26 campaign is warranted because of the continuing shift between JN.1 and the currently circulating subvariants.

The LP.8.1 strain, a subvariant of the JN.1 strain that was targeted last year, has begun spreading at a faster rate than other variants. It has already become dominant in different parts of the world such as the U.S. and is spreading in Europe.

Data from the Centers for Disease Control and Prevention showed that the LP.8.1 variant is estimated to account for about 70% of total cases in the U.S. over a two-week period ended May 10.

While the LP.8.1 is the predominant circulating strain, other virus subvariants, including LF.7 and XFG, have also been increasingly detected in recent weeks, the documents said.

Currently authorized vaccines in the U.S

Three COVID-19 shots have been authorized for use in the U.S. — Moderna (MRNA.O), Pfizer-BioNTech’s (PFE.N/22UAy.DE) messenger RNA-based vaccines, as well as Novavax’s (NVAX.O) protein-based shot that takes longer to manufacture.

Shares of Moderna jumped 9%, while Pfizer and Novavax rose 2% each.

Novavax gets FDA approval with restrictions

Novavax’s vaccine received its long-awaited FDA approval this week, after the regulator missed its April 1 deadline to green light the shot. The FDA, however, limited the vaccine’s use to individuals aged 65 and older and people over 12 years who have at least one underlying condition that puts them at high risk due to the illness.

Separately, the FDA said on Tuesday it plans to require new clinical trials for approval of annual COVID-19 boosters for healthy Americans under 65 years.

This effectively limits their availability this fall to older adults and those with a higher risk of developing severe illness, FDA leaders said.