# Moderna mRNA flu vaccine US approval > Live situation record from CLSTR: https://clstr.news/situations/moderna-mrna-flu-vaccine-us-approval > Updated: 2026-08-23T04:00:00.000Z. Sources: 68. Developments: 4. In early August 2026, the U.S. Food and Drug Administration (FDA) authorized Moderna’s mRNA-based seasonal influenza vaccine, mFlusiva. On 6 August, the agency granted full approval for adults aged 50–64, based on a late-stage trial involving over 40,000 participants that showed a roughly 27% reduction in flu cases compared to standard vaccines. Adults 65 and older received accelerated approval based on an immunogenicity study, with a confirmatory trial required to confirm effectiveness in preventing severe outcomes like hospitalization and death. On 8 August, the FDA issued an emergency use authorization (EUA) for the vaccine, covering adults 50 and older. This action was intended to diversify the U.S. flu-vaccine supply chain and address the high burden of influenza-related hospitalizations and deaths among older adults. The approval process was marked by initial delays, as the FDA had originally declined to review the application due to trial design concerns before reversing its decision following a dispute from Moderna. By 14 August, independent advisory committees voted unanimously that the benefits of the vaccine outweigh its risks. The vaccine is expected to be available this fall. The regulatory endorsement of mFlusiva—the first mRNA platform for seasonal influenza in the U.S.—comes amid political scrutiny of the technology. Health and Human Services Secretary Robert F. Kennedy Jr. has criticized mRNA platforms and previously canceled several federal mRNA development projects. Despite these concerns, the vaccine's ability to transition from strain selection to production in two to three months—significantly faster than the six-month cycle for traditional egg-based vaccines—positions it for distribution during the 2026–27 flu season. ## Claims - The FDA approved Moderna's mRNA-based influenza vaccine, mFLUSIVA, for adults aged 50 and older. (corroborated by 10 sources) - Moderna expects mFLUSIVA to be available for the 2026-2027 respiratory virus season. (corroborated by 5 sources) - As Health and Human Services Secretary, Robert F. Kennedy Jr. has criticized mRNA technology and previously canceled 22 federal mRNA vaccine development projects. (corroborated by 5 sources) - The FDA initially refused to review Moderna's application before reversing its decision following a dispute from the company. (corroborated by 5 sources) - mFLUSIVA was granted full approval for adults aged 50 to 64 and accelerated approval for those aged 65 and older. (corroborated by 4 sources) - In a study of over 40,000 participants, mFLUSIVA was approximately 26.6% to 27% more effective than standard-dose flu vaccines. (corroborated by 4 sources) - Reported side effects included injection-site pain, fatigue, headache, muscle aches, nausea, and fever. (corroborated by 2 sources) - The mRNA platform allows for a production timeline of two to three months from strain selection, compared to six months for traditional egg-based vaccines. (corroborated by 2 sources) ## Timeline ### 2026-08-23: Moderna's mFLUSIVA receives FDA approval as first mRNA flu vaccine The FDA has approved Moderna’s mFLUSIVA, the first mRNA-based flu vaccine, for adults aged 50 and older, showing higher efficacy in clinical trials for the 50–64 age group. 3 sources. https://clstr.news/cluster/modernas-mflusiva-receives-fda-approval-as-first-mrna-flu-vaccine ### 2026-08-14: FDA approves Moderna’s first mRNA flu vaccine for older adults The FDA has approved Moderna’s mFlusiva, the first mRNA-based flu vaccine for adults 50 and older, offering a faster and potentially more effective response to mutating influenza strains. 3 sources. https://clstr.news/cluster/fda-approves-modernas-first-mrna-flu-vaccine-for-older-adults ### 2026-08-08: Moderna's mFLUSIVA receives FDA approval as first mRNA flu vaccine The FDA has approved Moderna's mFLUSIVA, the first mRNA-based seasonal flu vaccine for adults aged 50+, showing higher efficacy than traditional options. 11 sources. https://clstr.news/cluster/fda-grants-emergency-use-authorization-to-modernas-mrna-flu-vaccine ### 2026-08-06: Moderna's mFlusiva mRNA Flu Vaccine Approved by US FDA The FDA approved Moderna’s mFlusiva, the first mRNA flu vaccine, for adults 50+. Full approval for ages 50‑64 (27% efficacy) and accelerated approval for 65+, with no major safety issues and limited supply for 52 sources. https://clstr.news/cluster/modernas-mrna-flu-vaccine-mflusiva-receives-fda-approval --- Cite as: Moderna mRNA flu vaccine US approval. CLSTR, https://clstr.news/situations/moderna-mrna-flu-vaccine-us-approval