The US FDA has approved Mflusiva (mRNA-1010), Cambridge, Massachusetts-based Moderna's (Nasdaq: MRNA) mRNA-based seasonal influenza vaccine, for active immunization against influenza A and B in adults 50 years and older — marking the first mRNA vaccine for influenza to receive regulatory approval anywhere.
The approval is two-tiered: full approval for adults aged 50 through 64, based on demonstrated relative vaccine efficacy (rVE) data, and accelerated approval for adults 65 and older, based on immunogenicity. Continued approval in the older cohort is contingent on verification of clinical benefit in a postmarketing confirmatory trial. The FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) had unanimously recommended the vaccine prior to approval. Moderna said it expects supply to be available in select US retailers in time for the 2026–2027 respiratory season, alongside its existing mRNA respiratory portfolio.
The full approval for the 50–64 age group rests on NCT06602024, a randomized, observer-blind, active-controlled Phase III trial enrolling 40,805 adults aged 50 and older across 11 countries. Primary objectives included safety and reactogenicity assessment and rVE against RT-PCR-confirmed influenza-like illness caused by any influenza A or B strain, compared with a standard-dose inactivated comparator. The accelerated approval for adults 65 and older drew on a separate immunogenicity trial (NCT05827978) enrolling 2,992 US adults in that age group, comparing Mflusiva against a high-dose inactivated influenza vaccine. Moderna said the Phase III program demonstrated an acceptable safety profile with no new safety concerns identified.
Mflusiva delivers lipid nanoparticle-encapsulated mRNA encoding hemagglutinin antigens from four influenza strains (quadrivalent: H1N1, H3N2, B/Victoria, B/Yamagata), directing host cells to produce antigen and elicit humoral and cellular immune responses without live virus or adjuvant. The platform is the same messenger RNA and lipid nanoparticle technology underpinning Moderna's approved COVID-19 vaccines.