BY MIRABEL ODETA
The U.S. Food and Drug Administration is set to convene its advisory panel on Thursday to vote on whether COVID-19 vaccines for the 2026–2027 immunization season should be updated to target the currently dominant XFG variant, as regulators grapple with evolving virus patterns and declining surveillance data quality.
The meeting of the FDA’s Vaccine and Related Biological Products Advisory Committee comes amid concerns raised by agency staff over limited and incomplete data on circulating COVID-19 strains, which has made it more difficult to track the virus’s ongoing evolution with precision.
Despite broader political changes under Health Secretary Robert F. Kennedy Jr., the panel will meet without membership alterations, which officials view as a sign of procedural continuity following a period of policy disruption in vaccine oversight and advisory processes.
In recent years, vaccine policy has experienced significant uncertainty, including legal challenges that temporarily halted decisions by the Centers for Disease Control and Prevention’s advisory structures. A court had previously stayed certain recommendations related to childhood vaccinations, including COVID-19 shots, citing procedural issues in how advisory members were appointed.
Ahead of Thursday’s vote, FDA briefing documents highlighted growing concerns about weakened virologic surveillance in the United States. Officials noted declines in sequencing capacity, reduced data submissions, and slower reporting from state and local public health departments, all of which have made it harder to accurately assess which variants are currently dominant.
The CDC’s COVID-19 dashboard currently reflects these data gaps, with weekly updates unavailable due to insufficient sequencing submissions. The most recent available data, now about a month old, indicated that XFG variants accounted for more than half of U.S. COVID-19 cases over a four-week period ending April 11.
Experts say the reduction in sequencing is driven by both declining public health staffing and reduced academic funding for large-scale viral monitoring programs. According to public health specialists, these gaps risk weakening early detection systems that have historically helped guide vaccine updates and public health responses.
For the 2025–2026 vaccination season, U.S. regulators had recommended that COVID-19 vaccines target the LP.8.1 subvariant, which is part of the broader JN.1 lineage that continues to generate new mutations and subvariants.
The FDA noted that while most current variants still descend from the JN.1 strain, newer sublineages such as NB.1.8.1 have also emerged in recent months, adding further complexity to vaccine strain selection decisions.
Earlier this month, the World Health Organization recommended that vaccine manufacturers consider targeting LP.8.1 or other actively circulating variants, including XFG and NB.1.8.1, reflecting a similar approach to balancing effectiveness with rapidly shifting viral evolution.
Several COVID-19 vaccines remain authorized in the United States, including mRNA-based shots from Moderna and Pfizer in partnership with BioNTech, as well as protein-based vaccines developed by Novavax and Sanofi.
The outcome of Thursday’s vote is expected to play a key role in shaping the composition of COVID-19 vaccines for the upcoming immunization cycle, as regulators attempt to balance scientific uncertainty, surveillance limitations, and the need to keep vaccines aligned with the most widely circulating strains.