VRBPAC Unanimous Vote Outcome

On June 18, 2026, the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) issued a unanimous 9-0 positive recommendation for Moderna's (MRNA) mRNA-based influenza vaccine, mFlusiva (developmental name mRNA-1010). Separate votes were held for traditional approval for the 50-64 age group and accelerated approval for the 65+ age group, and both votes resulted in unanimous approval, exceeding market expectations. The FDA initially rejected the application, but reversed its decision and began a review following public health concerns and the submission of additional data.

Phase 3 Clinical Data – Published in NEJM

The Phase 3 'Fluent' clinical trial, published in the New England Journal of Medicine (NEJM), was conducted in 11 countries with over 40,000 participants during the 2024-2025 Northern Hemisphere influenza season. The incidence of RT-PCR-confirmed influenza-like illness was 2.0% in the mRNA-1010 group versus 2.8% in the standard-dose control group, resulting in a relative vaccine efficacy (rVE) of 26.6%. In the 65+ subgroup, the rVE was 27.4%, with 29.6% for A/H1N1, 22.2% for A/H3N2, and 29.1% for B/Victoria, demonstrating consistent protection across subtypes. However, the FDA's statement regarding efficacy against influenza B remains cautiously worded, stating that it is 'not definitively established'.

Safety Profile and Regulatory Pathway

Reactogenicity, including injection site pain (65.8% vs. 29.8% in the control group), fatigue, arthralgia, and myalgia, was higher in the mRNA-1010 group, but was mostly mild to moderate and transient. Myocarditis/pericarditis was not reported, and the rate of serious adverse events was similar in both groups. As a condition for accelerated approval in the 65+ age group, a confirmatory trial is planned for two influenza seasons, involving up to 800,000 participants. William Blair analyst Myles Minter noted that there were 'no major deficiencies' in the FDA briefing document, and Leerink Partners' Mani Foroohar described it as a 'less-harsh regulatory stance'.

Market Competitive Landscape and Stock Reaction

The global influenza vaccine market is expected to grow from approximately USD 9.2 billion to 10.8 billion in 2025 to USD 19.2 billion to 30.8 billion in 2035. Currently, Sanofi (SNY), CSL Seqirus, and GSK (GSK) hold over 60% of the market share with their Fluzone/Flublok, cell-based vaccines, and AS03 adjuvant platform, respectively. A key differentiator for mFlusiva is that, due to the mRNA platform, it can reduce the production lead time from the current 6 months to 2-3 months in the event of a variant outbreak. On the day of the vote, MRNA's stock price rose 4% to USD 64.28, marking the largest weekly gain in over four years.