The Food and Drug Administration's independent vaccine advisory committee voted unanimously Wednesday to recommend updating COVID-19 vaccines to target the JN.1 variant lineage for the upcoming fall and winter season, marking another pivotal step in the ongoing effort to match vaccines with circulating virus strains.
All 16 committee members voted "yes" when asked whether they recommend a monovalent JN.1-lineage vaccine composition for the 2024-2025 formula. The decision now moves to the full FDA for final approval, with vaccine manufacturers prepared to begin production immediately upon authorization.
Current Vaccine Effectiveness Concerns Drive Update
The recommendation comes as studies demonstrate that currently available COVID-19 vaccines show reduced effectiveness against variants now in circulation. JN.1 and its descendants KP.2 and KP.3 represent the most common virus versions in the United States, according to the Centers for Disease Control and Prevention.
"Match does matter somewhat," said Dr. Jerry Weir, director of the Division of Viral Products in the Office of Vaccines Research and Review at the FDA's Center for Biologics Evaluation and Research. He noted that when manufacturers updated vaccines last year to better align with circulating variants, the changes appeared to offer improved protection.
Current Moderna and Pfizer/BioNTech mRNA vaccines target the KP.2 strain, while Novavax's protein-based shot already targets a JN.1 strain. The advisory panel expressed uncertainty about which specific JN.1 subvariant would prove optimal, as the dominant strain by fall remains unknown.
Manufacturing Timeline and Company Readiness
Vaccine manufacturers presented data showing their JN.1-targeted formulations demonstrate strong protection against current virus strains in animal and laboratory studies. The companies have already begun preparatory work for the anticipated strain change.
Novavax indicated its updated shot would need to target JN.1 specifically due to its six-month protein vaccine manufacturing timeline, with potential delivery to U.S. warehouses by August. The company has been developing this version in anticipation of the recommendation.
Pfizer and Moderna's mRNA platforms offer greater manufacturing flexibility, with both companies capable of producing either JN.1 or KP.2-targeted vaccines. Moderna projects mid-August supply availability, while Pfizer states its shot could be ready immediately upon approval.
Current Epidemiological Landscape
COVID-19 cases remain relatively low, with only 3% to 4% of tested individuals showing positive results, compared to 30% positivity rates during the peak Omicron surge in late 2021. Hospitalization rates have reached their lowest levels since March 2020, according to Dr. Natalie Thornburg, acting chief of the Laboratory Branch of the Coronavirus and Other Respiratory Viruses Division at the CDC.
Despite low current transmission, COVID-19 continues to cause significant morbidity and mortality. During fall and winter months last season, the virus hospitalized more than 500,000 Americans and caused 40,000 deaths, with unvaccinated individuals facing the highest risk of severe outcomes.
Vaccination Coverage Challenges
Current vaccine uptake remains suboptimal, with only approximately 25% of adults receiving the most recent updated shot. Among hospitalized children, half had no underlying medical conditions, emphasizing the importance of vaccination across all age groups regardless of baseline health status.
"This, I think, emphasizes the need for vaccination regardless of underlying condition, status or age," said Dr. Ruth Link-Gelles, vaccine effectiveness program lead with the National Center for Immunization and Respiratory Diseases.
Viral Evolution Patterns
The recommendation reflects the current state of SARS-CoV-2 evolution, which has become endemic in the United States and other countries. Rather than evolving into dramatically different strains that might pose greater risk, the virus continues producing new omicron subvariants with incremental changes.
This evolutionary pattern has enabled the continued use of updated vaccines targeting specific variant lineages, rather than requiring completely reformulated approaches. The World Health Organization has issued similar recommendations for JN.1-targeted vaccines, providing international alignment on the strain selection strategy.
The FDA's final decision on vaccine composition will determine the specific JN.1 subvariant to target, working closely with manufacturers to optimize protection against anticipated fall and winter circulation patterns.
