The Food and Drug Administration’s panel of vaccine advisers will consider which COVID-19 strains the agency should direct manufacturers to target in the fall.
The FDA Vaccines and Related Biological Products Advisory Committee is scheduled to meet on May 28 and vote on whether vaccines should be reformulated to target XFG variants.
The FDA has for years been advising companies to update shots annually, to try to address lower and waning effectiveness, and it followed the recommendation of the advisory committee in 2025 to direct manufacturers to target a variant called LP.8.1.
In late 2025 and early 2026, Pfizer and Moderna produced vaccines targeting LP.8.1, while Novavax’s shot targeted JN.1. XFG and LP.8.1 are both JN.1 sublineages, but LP.8.1 has virtually disappeared from the country.
XFG variants, including XFG 1.1, are dominant in the United States, according to estimates from the Centers for Disease Control and Prevention.
“Because of the continuing virus antigenic drift, a review and discussion regarding the need for a strain composition update for COVID-19 vaccines is warranted,” FDA officials said in a briefing document to its advisers released ahead of the May 28 meeting.
“[The manufacturers of COVID-19 vaccines] have indicated that they are prepared to produce an XFG vaccine,” FDA officials said.
They also noted that BA.3.2, derived from the Omicron strain, and known as the Cicada variant, has been increasing in circulation in some areas, but is only a minor variant in the United States
Vaccines and Related Biological Products Advisory Committee members will listen to presentations on COVID-19 strains and other data during the meeting before voting to recommend, or not recommend, that the FDA direct companies to reformulate vaccines with XFG.
During the meeting they will also discuss the circumstances that may warrant the recommendation of a non-JN.1. lineage variant, such as BA.3.2, for COVID-19 vaccines.
The World Health Organization’s advisory group on the composition of COVID-19 vaccines on May 16 said the recommended formulation was a monovalent shot against LP.8.1—the same recommendation offered in December 2025—based in part on animal data that indicated LP.8.1 vaccines induce protection against other lineages of JN.1.
“Overall, LP.8.1 as a vaccine antigen in populations with high levels of prior infection and / or vaccination continues to induce broadly cross-reactive immune responses to circulating SARS-CoV-2 variants,” the group stated. SARS-CoV-2 is the virus that causes COVID-19.
The group did say that other antigens, such as XFG, that “demonstrate broad and robust neutralizing antibody responses or efficacy” against circulating variants could be used in lieu of LP.8.1.