FDA Demands More Data on Moderna’s Quadrivalent mRNA Flu Vaccine, Approval Delayed
The FDA rejected Moderna’s supplemental biologics license application for its quadrivalent mRNA flu vaccine on February 11, citing insufficient immunogenicity data for A/H1N1 and A/H3N2 strains and requiring further lipid nanoparticle manufacturing validation. This decision pushes US approval beyond the 2026–2027 flu season and mandates additional mid-stage trials.
1. FDA Rejects Supplemental Application
On February 11, the FDA informed Moderna that its supplemental biologics license application for the quadrivalent mRNA flu shot failed to meet immunogenicity benchmarks for both A/H1N1 and A/H3N2 components. Regulators also flagged inconsistencies in lipid nanoparticle manufacturing data, requesting additional chemistry, manufacturing and controls (CMC) documentation.
2. Delay to 2026–2027 Flu Season
As a result, Moderna cannot market the vaccine in the US for the upcoming 2026–2027 flu cycle and must allow for extended review timelines. The setback interrupts Moderna’s aim to diversify its mRNA portfolio beyond COVID-19 into seasonal vaccines.
3. Next Steps and Trial Requirements
Moderna must conduct supplementary mid-stage studies to generate robust antibody response data and resubmit updated CMC validation reports. Only after satisfying these requirements will the FDA consider granting approval for US distribution.