Is the mRNA-Based Flu Vaccine Already Available?

The first mRNA flu vaccine in the United States began distribution at pharmacies across the country ahead of the 2026-2027 influenza season. The Food and Drug Administration (FDA) approved mFlusiva, by Moderna, in August 2026 exclusively for people 50 years or older.

What is the mRNA flu vaccine?

mFlusiva is the first influenza vaccine that uses messenger RNA (mRNA) technology in the United States. This platform is the same one used by Pfizer and Moderna’s COVID-19 vaccines during the pandemic.

Unlike traditional formulas, which use an inactivated version of the virus typically grown in eggs, mFlusiva uses a fragment of genetic code. That material temporarily trains the immune system to recognize and fight the influenza virus.

«It’s like a temporary instruction for your immune system to alert your body’s natural defenses to recognize the flu,» explained Emlah Tubuo, independent pharmacist from Ohio, to NBC News. The mRNA breaks down after fulfilling its function and does not remain in the body.

Protection takes approximately 2 weeks to develop after the injection. Like traditional vaccines this season, mFlusiva is trivalent, meaning it protects against 2 strains of influenza A and 1 strain of influenza B.

Who can receive the mFlusiva vaccine?

The FDA authorization limits this vaccine’s use exclusively to people 50 years or older. People younger than that age cannot receive it during the 2026-2027 flu season. The agency granted two types of authorization according to age group:

• Traditional authorization for adults ages 50 to 64.
• Accelerated authorization for people 65 years or older, subject to an additional clinical trial that Moderna must complete.

«If you haven’t turned 50 yet, this vaccine shouldn’t interest you,» noted Tubuo. People under 50 can receive one of the other traditional flu vaccines approved for their age.

Why did the FDA require an additional trial for older adults?

The controversy arose because Moderna compared mFlusiva with a standard-dose vaccine in people 65 years or older. However, the Centers for Disease Control and Prevention (CDC) recommend a high-dose vaccine for that specific age group.

The FDA initially refused to review Moderna’s application for that reason. Subsequently, the agency reversed course and accepted conducting an additional clinical trial after initial approval.

In June 2026, the FDA’s independent vaccine advisory panel unanimously recommended approving the vaccine for older adults. That endorsement allowed the vaccine to arrive in time for this year’s flu season.

How effective and safe is the vaccine?

An advanced-phase clinical trial, published in May 2026 in the New England Journal of Medicine, evaluated more than 40,000 adults 50 years or older in 11 countries, including the United States