The mRNA-based influenza vaccine is expected to be available in the coming weeks.
The Food and Drug Administration (FDA) has approved mFlusiva®, the first mRNA-based influenza vaccine, for adults aged 50 years and older. For persons aged 65 years and older, the vaccine received accelerated approval based on immune responses; continued approval in this age group is contingent upon verification and description of clinical benefit in a confirmatory postmarketing trial
Moderna’s mFlusiva is indicated for active immunization for the prevention of influenza disease caused by influenza virus subtypes A and type B contained in the vaccine. Each 0.38mL dose contains 3 RNAs encoding the hemagglutinin glycoproteins of the following seasonal influenza strains: A/Missouri/11/2025 (H1N1) pdm09-like virus; A/Michigan/105/2025, an A/Darwin/1415/2025 (H3N2)-like virus; and B/Pennsylvania/19/2025, a B/Pennsylvania/14/2025-like virus. These 3 influenza virus strains align with the FDA recommendations for the 2026-2027 influenza season.
The approval was supported by data from a phase 3 trial (ClinicalTrials.gov Identifier: NCT06602024) that compared mFlusiva with a standard-dose licensed inactivated seasonal influenza vaccine (Fluarix®) in individuals aged 50 years and older. Study participants were randomly assigned to receive a single intramuscular injection of trivalent mFlusiva or the standard-dose comparator.
Relative vaccine efficacy (rVE; primary endpoint) was assessed based on the time to first episode of reverse transcriptase-polymerase chain-reaction (RT-PCR)-confirmed, protocol-defined influenza-like illness (ILI) caused by influenza A or B from day 14 postvaccination up to the end of the influenza season
At a median follow-up of 181 days (range, 1 to 227), RT-PCR-confirmed, protocol-defined ILI occurred in 2% (411/20,179) of mFlusiva recipients and 2.8% (557/20,124) of standard-dose comparator recipients. This corresponded to an rVE of 26.6% (95% CI, 16.7-35.4) in the overall study population, meeting the prespecified criterion for superiority. In a subgroup analysis of individuals aged 65 years and older, mFlusiva demonstrated an rVE of 27.4%
To further evaluate immunogenicity and safety in individuals aged 65 years and older, a second phase 3 study (ClinicalTrials.gov Identifier: NCT05827978) was conducted in which randomized participants to receive either the mRNA influenza vaccine (a quadrivalent formulation; n=1425) or a high-dose inactivated influenza vaccine comparator (Fluzone® High-Dose Quadrivalent; n=1409).
Findings demonstrated that the mRNA influenza vaccine met all coprimary immunogenicity endpoints for all vaccine-matched influenza strains. Confirmation of clinical benefit in this demographic will be further assessed in a postmarketing trial
Regarding safety, the most common adverse reactions reported by age group included:
- Participants aged 50 to 64 years: injection site pain (68.7%), fatigue (48.1%), headache (41.9%), myalgia (40.6%), arthralgia (31.5%), chills (27.5%), and axillary swelling or tenderness (20.3%).
- Participants aged 65 years and older: injection site pain (62.9%), fatigue (42.1%), headache (33.7%), myalgia (30.2%), arthralgia (24.1%), chills (18.1%), and axillary swelling or tenderness (14.2%).
The mFlusiva vaccine is supplied as an injectable suspension in a single-dose prefilled syringe. It is administered intramuscularly as a single 0.38mL dose.
“The approval highlights the tremendous potential of mRNA vaccine technology,” said Ronald G. Nahass, MD, MHCM, FIDSA, President of the Infectious Diseases Society of America. “Unlike conventional manufacturing, the mRNA platform allows for streamlined development and rapid responses to emerging mutations in viruses. Demonstrating the success of mRNA for influenza opens the door to broader applications, accelerating our ability to create safe and targeted vaccines for a wider range of preventable diseases.”
The vaccine is expected to be available in the coming weeks
This article originally appeared on MPR
- Moderna receives US FDA approval for influenza vaccine mFlusiva. News release. Moderna. August 5, 2026.https://feeds.issuerdirect.com/news-release.html?newsid=4801915282452025&symbol=MRNA.
- MFlusiva. Package insert. Moderna; 2026. Accessed August 6, 2026.https://static.modernatx.com/pm/6cef78f8-8dad-4fc9-83d5-d2fbb7cff867/fd4a111d-2fbe-443d-81c8-e4f40c85c7a8/fd4a111d-2fbe-443d-81c8-e4f40c85c7a8_viewable_rendition__v.pdf.
