The Food and Drug Administration’s panel of vaccine advisers on May 28 recommended that the next round of COVID-19 vaccines target the XFG COVID-19 variant.
Eight of the nine members of the Vaccines and Related Biological Products Advisory Committee who voted during a meeting said that the next vaccines should be monovalent, or only include one antigen, and that the preferred antigen is XFG.
XFG variants, including XFG 1.1, are dominant in the United States, according to estimates from the Centers for Disease Control and Prevention.
The FDA has for years directed vaccine manufacturers to update their shots on an annual basis, to try to strengthen vaccine effectiveness.
The 2025–2026 versions of vaccines from Pfizer and Moderna targeted LP.8.1, while Novavax’s targeted JN.1. Those vaccines were estimated to initially provide 58 percent protection among adults described as immunocompetent against hospitalization, according to a May 28 presentation from the CDC.
LP.8.1 and XFG are JN.1. sublineages.
FDA officials told advisers during the meeting that COVID-19 vaccine manufacturers are all prepared to produce an XFG vaccine if that was recommended.
The vaccines would be produced in the coming months and become available in the fall and winter, when respiratory illnesses are more prevalent.
Officials with the FDA and vaccine manufacturers presented data from animal testing that indicated XFG-based vaccines induced antibodies against XFG and other JN.1 sublineages.
Adam Berger, a global health expert who works for the National Institutes of Health and one of the advisers, said he voted in support because it “seemed like the reactivity that we’re getting with the current serum and other preclinical data seems to indicate that it actually has fairly good reactivity across the entirety of the JN.1 lineage itself, as well as inducing reactivity against BA.3.2,” a strain that has been growing prominent in some areas.
Dr. Hana El Sahly, a professor of molecular virology and microbiology at the Baylor College of Medicine and another adviser, said she abstained from the vote because she read the data as showing XFG-based vaccines were not far superior than the most recently updated versions of the shots.
The FDA in 2025 approved two vaccines from Moderna, one from Pfizer, and one from Novavax for many Americans. The CDC then instructed people to speak with healthcare professionals before getting vaccinated, in part due to concerns of side effects.
A federal judge blocked the CDC’s update, ruling that those and other changes to vaccine guidance were not done in the proper manner.
An appeal is pending.