Moderna's mRNA flu vaccine approved for adults 50 and older

The U.S. Food and Drug Administration (FDA) has approved mFLUSIVA (mRNA-1010), a new influenza vaccine from Moderna, for adults aged 50 and older. This is the first vaccine to use mRNA technology for flu prevention, marking a shift in how the virus is addressed. Its approval follows a Phase 3 trial involving more than 40,000 adults across 11 countries. The results showed a relative vaccine efficacy of 26.6% compared to standard-dose flu vaccines, while for those 65 and older, that figure was 27.4%. Moderna expects to have the vaccine available at select retail locations in time for the 2026–2027 respiratory virus season.

Influenza has long been a difficult challenge for public health, especially among older populations. Those aged 65 and older represent a large majority of flu-related hospitalizations and deaths. The approval of mFLUSIVA introduces a different mechanism through lipid nanoparticle-encapsulated mRNA. Instead of using traditional methods, this approach instructs cells to produce hemagglutinin proteins, which prime the immune system and may offer better protection against shifting viral strains. This is a significant development, as the effectiveness of conventional vaccines can vary due to the naturally weakening immune responses in older adults.

The path to approval involved extensive clinical testing and regulatory oversight. During the Phase 3 trial (NCT06602024), researchers compared the safety and efficacy of mFLUSIVA against an existing licensed standard-dose vaccine. The study successfully met its co-primary endpoints for both safety and efficacy against confirmed cases of influenza. Reactions were generally mild or moderate, with injection site pain and fatigue being the most common reports. No new safety signals were found, which supports the vaccine's use for older adults who may be managing other health conditions.

While the influenza vaccine market already includes established high-dose and adjuvanted options, this new mRNA technology offers a distinct alternative. The FDA's recommendation for its use in adults aged 50 and older was unanimous, reflecting a clear consensus on its benefit-risk profile. Regulatory reviews are currently underway in the European Union, Canada, and Australia, with more submissions planned for the coming year. This international expansion could broaden the tools available globally to manage seasonal flu.

The introduction of mFLUSIVA marks a notable point in addressing the risks influenza poses to older adults. Once available, the vaccine is intended to help raise vaccination rates and lower the number of hospitalizations and deaths linked to the virus. The adaptability of mRNA technology suggests further possibilities for vaccine development as the influenza virus continues to change. Ongoing monitoring and postmarketing studies will continue to track the clinical benefits of mFLUSIVA, ensuring it meets the specific needs of high-risk populations in the future.