The U.S. Food and Drug Administration's advisory panel is set to vote on a critical decision Thursday: whether COVID-19 vaccines for the 2026-2027 immunization campaign should target the dominant XFG variant. This pivotal meeting follows concerns raised by FDA staff regarding limited data on currently circulating strains of the virus.
Procedural Normalcy Amid Turmoil
The FDA's Vaccine and Related Biological Products Advisory Committee will convene with its membership unchanged by Robert F. Kennedy Jr., signaling a measure of procedural normalcy. This follows a period of significant vaccine policy shake-ups under the health secretary. Furthermore, vaccine regulation has been in limbo since a court imposed a stay on decisions by the CDC's advisory panel to drop recommendations for childhood vaccines, including the COVID shot, citing Kennedy's failure to properly appoint that specific panel.
Data Gaps and Surveillance Decline
In briefing documents released ahead of this week's meeting, the FDA articulated that assessing the ongoing evolution of COVID-19 has become progressively more difficult. This challenge stems from a notable decline in virologic surveillance, reduced sequencing volumes, and a lack of timely data sharing from state and local public health departments. The Centers for Disease Control and Prevention's COVID dashboard starkly reflects this data gap, with weekly data currently unavailable due to insufficient sequencing submissions.
The most recent update, now over a month old, indicated that XFG strains alone accounted for more than half of all U.S. cases during the four weeks concluding April 11. Jill Roberts, an associate professor at the University of South Florida College of Public Health, explained this reduction in sequencing as a consequence of both the loss of government surveillance staff and diminished academic funding.
Variant Evolution and Vaccine Landscape
For the preceding 2025-26 season, the FDA had previously recommended that COVID shots target LP.8.1, a subvariant of the broader JN.1 strain. While COVID variants continue to be primarily derived from the JN.1 strain, other distinct subvariants, such as NB.1.8.1, have emerged since May of last year, according to the FDA's comprehensive briefing documents. Currently, four COVID shots have received approval for use in the U.S.: Moderna's mNEXSPIKE and Spikevax, Pfizer-BioNTech's Comirnaty (three of which are mRNA-based vaccines), and Novavax-Sanofi's protein-based shot, which typically requires a longer manufacturing process.
