FDA Approves mFlusiva: The First mRNA Flu Vaccine for Adults 50 and Older

FDA Approves mFlusiva, the First mRNA Flu Vaccine, for Adults 50 and Older

The United States Food and Drug Administration (FDA) has approved mFlusiva (mRNA-1010), the first influenza vaccine built on mRNA technology, for the prevention of seasonal flu in adults aged 50 years and older. The landmark approval, announced by Moderna on August 5, 2026, marks a new era in flu prevention and gives older adults a powerful new option ahead of the 2026-2027 respiratory virus season.

The decision follows unanimous recommendations from the FDA Vaccines and Related Biological Products Advisory Committee (VRBPAC) and makes mFlusiva the first mRNA-based influenza vaccine to reach the United States market. It is ModernaIt is Moderna fifth approved product globally#8217;s fifth approved product globally and its fourth FDA-approved product.

What Is mFlusiva and How Does the mRNA Flu Vaccine Work?

mFlusiva is a seasonal influenza vaccine that uses messenger RNA (mRNA) technology, the same platform behind the highly successful COVID-19 vaccines. Instead of using inactivated or weakened virus, mRNA vaccines teach the body cells to produce a harmless piece of the flu virus surface protein. The immune system then learns to recognise and attack the real virus if it appears.

This approach offers several advantages over traditional flu shots:

• Faster production: mRNA vaccines can be manufactured and updated more quickly when new flu strains emerge.
• Egg-free manufacturing: Unlike many conventional flu vaccines, mRNA vaccines do not rely on chicken eggs, reducing supply bottlenecks.
• Better strain match potential: The platform allows developers to target multiple strains and adjust quickly to circulating viruses.
• Proven platform: mRNA technology has now been validated across COVID-19, RSV and influenza vaccines.

Clinical Trial Results: What the Evidence Shows

Approval for adults aged 50 to 64 years is based on the Phase 3 FLUENT trial (NCT06602024), a randomised, observer-blind, active-controlled study that enrolled 40,805 adults aged 50 years and older across 11 countries. The trial compared mFlusiva with a standard-dose influenza vaccine and measured relative vaccine efficacy against RT-PCR-confirmed, protocol-defined influenza-like illness caused by influenza A or B strains.

The study showed that mFlusiva provided superior protection compared with the standard-dose flu vaccine, meeting the pre-specified superiority criteria in adults aged 50 to 64 years.

For adults aged 65 years and older, the FDA granted accelerated approval based on a randomised, observer-blind, active-controlled immunogenicity trial (NCT05827978) that enrolled 2,992 adults in the United States. In that study, mFlusiva was compared with a high-dose inactivated influenza vaccine. The effectiveness of mFlusiva in this older group is also supported by descriptive relative vaccine efficacy analyses from the Phase 3 trial. A postmarketing confirmatory trial is required to verify clinical benefit in adults 65 and older.

Safety Profile and Common Side Effects

The Phase 3 program demonstrated an acceptable safety profile with no new safety concerns identified, consistent with earlier mFlusiva studies. Reported side effects include:

• Injection site reactions such as pain, tenderness, redness, swelling and swollen lymph nodes in the injected arm
• Fatigue and headache
• Muscle pain and joint pain
• Chills, nausea or vomiting, and fever

Severe allergic reactions are rare but can occur, usually within minutes to an hour after vaccination. People who have had a severe allergic reaction to any ingredient of mFlusiva should not receive it. Anyone with a history of Guillain-Barré syndrome after a flu vaccine, a weakened immune system, or who is pregnant or breastfeeding should discuss vaccination with their healthcare provider first.

When Will the mRNA Flu Vaccine Be Available?

Moderna expects mFlusiva to be available in select retailers in the coming weeks, in time for the 2026-2027 respiratory virus season. It joins the company respiratory portfolio, which includes Spikevax and mNEXSPIKE (COVID-19 vaccines) and mRESVIA (respiratory syncytial virus vaccine).

Regulatory review is also underway in the European Union, Canada and Australia, with submissions in additional countries planned during 2026.

Why This Matters for Public Health

Influenza remains a serious public health threat, causing hundreds of thousands of hospitalisations and tens of thousands of deaths worldwide each year. Older adults bear the heaviest burden, yet conventional flu vaccines often provide only moderate protection in this group. The arrival of an mRNA flu vaccine offers the potential for improved efficacy, faster strain updates and a more resilient seasonal vaccine supply.

Frequently Asked Questions

Q: Who is eligible for the mFlusiva mRNA flu vaccine?
A: mFlusiva is approved for adults aged 50 years and older. Adults 50 to 64 receive full approval based on clinical efficacy data, while adults 65 and older receive accelerated approval based on immune response data, with confirmatory studies ongoing.

Q: How effective is the mRNA flu vaccine compared with traditional flu shots?
A: In the Phase 3 FLUENT trial, mFlusiva demonstrated superior relative vaccine efficacy compared with a standard-dose flu vaccine in adults aged 50 to 64 years.

Q: What side effects can I expect from mFlusiva?
A: The most common side effects are injection site pain and tenderness, fatigue, headache, muscle and joint pain, chills and mild fever. These usually resolve within a few days.

Q: Can I get mFlusiva at the same time as other vaccines?
A: Talk to your healthcare provider about co-administration with other vaccines, such as COVID-19 and RSV shots, and about what is recommended for your individual situation.

Q: Will the mRNA flu vaccine replace traditional flu vaccines?
A: Not immediately. mFlusiva adds a new option, particularly for older adults, while traditional egg-based and cell-based flu vaccines remain widely available.

Q: Is mFlusiva available outside the United States?
A: Regulatory review is underway in the European Union, Canada and Australia. Availability in other countries will depend on each regulator approval.

Disclaimer: This article is for information only and is not medical advice. Always consult a qualified healthcare professional about vaccination decisions for you or your family.