FDA advisers weigh updating COVID shots for XFG variant

The clearest issue before FDA vaccine advisers was whether next fall’s COVID shots would still match the virus people are most likely to face. On May 28, the Vaccines and Related Biological Products Advisory Committee voted to update the 2026-2027 formula so it would target XFG, the dominant variant now driving the agency’s discussion of strain selection for the U.S. market.

The panel’s recommendation, which Reuters reported passed 8-1 with one abstention, came after FDA staff told advisers that manufacturers had said they were ready to make an XFG vaccine for the 2026-27 season. That matters because each seasonal update depends on both the speed of the virus and the speed of production: regulators have to choose a strain early enough for companies to manufacture doses, distribute them and position pharmacies and clinics before the fall campaign begins.

The vote also landed in a political and legal climate that has made vaccine governance unusually fragile. A federal judge in Massachusetts issued a preliminary injunction in March 2026 staying Robert F. Kennedy Jr.’s appointments to the CDC’s Advisory Committee on Immunization Practices and staying votes taken by that newly constituted panel. Against that backdrop, the FDA meeting signaled an effort to keep the federal vaccine process functioning with a measure of continuity, even as leaders, courts and advisory bodies remain in conflict.

International guidance pointed in a slightly different direction. The World Health Organization’s May 16, 2026 statement recommended monovalent LP.8.1 as the preferred antigen for updated vaccines, while saying XFG and NB.1.8.1 could also be used. The WHO had asked in March for data to inform its May antigen-composition deliberations, underscoring how closely regulators around the world are tracking the same shifting set of variants. WHO’s risk assessment said XFG is a recombinant of LF.7 and LP.8.1.2, with the earliest sample collected on January 27, 2025.

The U.S. market already has four approved COVID vaccines: Moderna’s MNEXSPIKE and SPIKEVAX, Pfizer-BioNTech’s COMIRNATY and Novavax’s NUVAXOVID. Reuters said Moderna told the panel it could supply the recommended composition by mid-August, and Novavax’s vaccine licensing deal with Sanofi, struck in 2024 and worth at least $1.2 billion, gives that supply chain broader commercial backing. CDC data released May 26 showed U.S. COVID infections were declining overall, with emergency-department visits for COVID described as very low, but variant surveillance remains central to whether the fall shots will be aimed at the strain people actually encounter.