FDA Advisory Panel Votes to Update COVID-19 Vaccines to Target XFG Variant for 2026-2027 Season
核心洞察
The FDA's Vaccines and Related Biological Products Advisory Committee voted to update COVID-19 (搜索) vaccines to target the XFG variant (搜索) for the 2026-2027 immunization season.
XFG currently accounts for more than half of U.S. COVID-19 (搜索) cases and has been the dominant circulating variant globally for over six months.
All four FDA-approved vaccine manufacturers indicated readiness to produce updated formulations, with Moderna prepared to supply by mid-August and Sanofi already manufacturing XFG-targeting vaccines.
The FDA's Vaccines and Related Biological Products Advisory Committee has voted in favor of updating COVID-19 (搜索) vaccines to target the XFG variant (搜索) for the 2026-2027 immunization season, marking a significant shift in vaccine strategy as the virus continues to evolve.
The decision addresses the dominance of the XFG variant (搜索), which currently accounts for more than half of U.S. cases based on the most recent available CDC (搜索) data. According to Sanofi, XFG has been the dominant circulating variant globally for more than six months and offers broad protection across the JN.1 lineage (搜索).
Vaccine Manufacturer Readiness
All four manufacturers of FDA-approved COVID-19 (搜索) vaccines have indicated their preparedness to move quickly on updated formulations. As of May 28, 2026, the approved vaccines include Moderna's mNEXSPIKE (搜索) and Spikevax, Pfizer-BioNTech (搜索)'s Comirnaty, and Novavax-Sanofi's protein-based vaccine.
Moderna has stated it is prepared to supply the recommended composition by mid-August, while Pfizer and BioNTech say they are ready to supply an updated formula upon approval. Sanofi, which partners with Novavax on a protein-based shot that requires longer manufacturing times than mRNA vaccines, is already manufacturing XFG-targeting vaccines for the 2026-2027 season.
"Sanofi welcomes the recommendation of XFG as the strain for the 2026–2027 COVID-19 (搜索) vaccine season," a Sanofi spokesperson said in an email. "This decision reflects the scientific evidence supporting XFG as the dominant circulating variant globally for more than six months, offering broad protection across the JN.1 lineage (搜索)."
Surveillance Data Challenges
The advisory panel's decision comes amid significant concerns about the quality and availability of surveillance data used to inform vaccine composition decisions. FDA staff raised concerns in briefing documents about the limited and deteriorating quality of data on currently circulating strains.
The agency noted that assessing COVID-19 (搜索)'s evolution has become increasingly difficult as virologic surveillance, sequencing volumes, and timely data sharing from state and local public health departments have declined. The CDC (搜索)'s COVID dashboard reflects this gap directly, with weekly data currently unavailable due to low sequencing submissions, leaving the panel working from information that is weeks out of date.
Jill Roberts, associate professor at the University of South Florida College of Public Health, attributed the reduced sequencing to the loss of government surveillance staff and cuts to academic research funding. These structural changes are making real-time tracking of variant evolution harder to sustain.
Regulatory Context
The advisory committee meeting occurred during a period of significant changes in U.S. vaccine policy under Health Secretary Robert F. Kennedy Jr. The WHO, which the U.S. is no longer part of, had previously advised vaccine manufacturers to target the LP.8.1 subvariant (搜索) for several 2025-2026 COVID-19 (搜索) vaccines.
The VRBPAC briefing noted WHO's advice to select antigens for the LP.8.1 strain, though it also stated that "other antigens such as XFG or NB.1.8.1 could also be used." XFG is currently classified by WHO as a variant under monitoring.
Sanofi emphasized the importance of earlier strain selection, stating: "We also take this opportunity to reiterate the importance of selecting strains earlier, which is critical to ensuring all existing vaccines can be available for eligible patients on time and help maximize vaccination coverage rates ahead of the season."
The decision represents a return to more routine vaccine policy operations following months of turbulence, including delays in appealing a federal court ruling that halted key elements of childhood vaccine policy changes.