FDA Approves First mRNA Flu Vaccine for Adults 50 and Older
Key Takeaways
-
The FDA approved mFlusiva, the first mRNA flu vaccine, for adults 50 and older.
-
In a large clinical trial, mFlusiva was about 27 percent more effective than a standard-dose flu vaccine at preventing flu.
-
Other flu shots are already starting to arrive at pharmacies; Moderna says mFlusiva should reach some retailers in the coming weeks.
The U.S. Food and Drug Administration (FDA) has approved the first mRNA flu vaccine in the United States, giving adults ages 50 and up a new option for the 2026-2027 flu season.
The vaccine, called mFlusiva, received full approval for adults ages 50 to 64 and accelerated approval for adults 65 and older (allowing people in this age group to get the vaccine while the company that makes mFlusiva, Moderna, completes an additional study to confirm its clinical benefit in this age group).
"This is really significant," says Paul Pottinger, MD , director of the Infectious Diseases and Tropical Medicine Clinic at UW Medical Center in Seattle, and cohost of the travel health podcast Germ & Worm . "It gives us not only a new choice, but also a more nimble, responsive way to help prevent flu," he says.
Moderna is studying mFlusiva in younger age groups, but more data are needed before the FDA could expand its approval, says Dr. Pottinger.
"Since older people don't typically respond as well to traditional flu vaccines, the idea here was to develop a shot that works better in people over 50," says David Wohl, MD , a professor of medicine at UNC Chapel Hill in North Carolina and an infectious disease expert. Younger adults produced even stronger immune responses in earlier research, although they also had more short-term side effects after the shot, he says.
Why an mRNA Flu Vaccine Is a Big Deal
Flu vaccines have to be updated every year because influenza viruses are constantly changing. Most traditional flu vaccines are grown in chicken eggs, a process that can take six months or longer, so scientists have to choose which strains to target long before flu season begins, says Pottinger. Those decisions are informed in part by which flu viruses circulate earlier in the year in the southern hemisphere.
mRNA vaccines are made differently. mFlusiva uses lab-made messenger RNA that gives the body's cells instructions for producing proteins found on the surface of the targeted flu viruses. The immune system learns to recognize those proteins, so the body is prepared to respond if it encounters the viruses later.
One advantage of that approach is speed. Moderna says mFlusiva can go from strain selection to production in about two to three months, compared with roughly six months for traditional flu vaccines, says Pottinger.
"Sometimes that means we have a mismatch between what's actually coming in the fall and what we made in the spring," he says. With mRNA technology, vaccine makers can select strains closer to flu season, reducing the window in which the virus can change before people are vaccinated.
mFlusiva Was More Effective Than a Standard Flu Shot in Clinical Trials
The FDA's decision for adults ages 50 to 64 was based on a late-stage trial of more than 40,000 adults in 11 countries. In the trial, mFlusiva was about 27 percent more effective than a standard-dose flu vaccine at preventing laboratory-confirmed influenza in adults 50 and older.
For people 65 and older, accelerated approval was based largely on a separate study of nearly 3,000 adults that found mFlusiva generated a strong immune response compared with a high-dose flu vaccine.
No new safety concerns were identified. Common reactions included injection-site pain, fatigue, headache, muscle and joint pain, chills, nausea, and fever.
The FDA Initially Refused to Review mFlusiva
Earlier this year, the FDA refused to accept Moderna's application for review because the company's large trial compared mFlusiva with a standard-dose flu shot in adults 65 and older.
Moderna pushed back, saying FDA staff had previously agreed to the study design. The company also pointed to its separate study comparing mFlusiva with a high-dose vaccine in older adults.
The FDA subsequently agreed to review a revised application: full approval for ages 50 to 64 and accelerated approval for people 65 and older, with additional research required. In June, the agency's independent vaccine advisory committee unanimously recommended approval for both groups.
"This is a remarkable turn of events from the FDA. It is quite the about-face from just a few months ago," says Scott Roberts, MD , an assistant professor of infectious diseases at Yale School of Medicine in New Haven, Connecticut.
What Flu Strains Will mFlusiva Target?
The new mFlusiva shot adds another option, rather than replacing existing flu vaccines. Updated versions of the usual options are also expected, including:
-
Standard-dose inactivated flu shots
-
High-dose and adjuvanted (boosted) shots for older adults
-
The FluMist nasal spray
All U.S. flu vaccines for the 2026-2027 season will protect against three viruses:
-
An influenza A(H1N1) virus
-
An A(H3N2) virus
-
A B/Victoria-lineage virus
All three components have been updated since last season, including a change intended to better protect against the H3N2 subclade K virus that spread widely during the 2025-2026 season.
Dr. Roberts says it's still too early to know how severe the upcoming U.S. flu season will be.
"The southern hemisphere is in peak flu season now, so the data are yet to come about overall flu season severity; H3N2 seems predominant, and flu B is currently on the rise," says Roberts.
When Will mFlusiva Be Available, and When Should You Get a Flu Shot?
Other flu vaccine brands have already started arriving at pharmacies, and Moderna says mFlusiva should be available at select retailers in the coming weeks.
One complication is that the Centers for Disease Control and Prevention (CDC) vaccine advisory committee has not yet formally recommended mFlusiva and is currently blocked from meeting by a federal court order. That could affect insurance coverage, even though the FDA-approved vaccine can legally be given.
For most adults, Roberts recommends getting vaccinated in October, so protection is strong when flu typically picks up in December and January and lasts into the spring. CDC guidance similarly identifies September and October as the best vaccination window for most people.
Timing can vary because of travel or other circumstances, Dr. Wohl says, "but certainly well before Thanksgiving."
And for anyone wondering whether to hold out for mFlusiva rather than get another available vaccine, Pottinger offers a simple rule: "The best flu shot you can get is the one you do get."
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy . We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
-
Moderna Receives U.S. FDA Approval for Influenza Vaccine mFLUSIVA. Access Newswire . August 5, 2026.
-
FDA Briefing Document BLA# 125869/0 Influenza Vaccine, mRNA (Proposed Trade Name: mFlusiva) Applicant: Moderna TX, Inc. U.S. Food and Drug Administration . June 18, 2026.
-
Fitz-Patrick D et al. Efficacy, Immunogenicity, and Safety of Modified mRNA Influenza Vaccine. The New England Journal of Medicine . November 20, 2025.
-
Malkin E et al. 229. mRNA-1010, an mRNA-Based Vaccine, is Safe and Efficacious in Adults Aged ≥50 Years. Open Forum Infectious Disease . January 11, 2026.
-
Neergaard L. FDA Panel Backs First-of-Its-Kind Flu Vaccine Using mRNA Technology. Associated Press . August 6, 2026.
-
Different Types of Flu Vaccines. Centers for Disease Control and Prevention . January 28, 2026.
-
2026-2027 Flu Season. Centers for Disease Control and Prevention . April 13, 2026.
-
Lovelace B. FDA Approves 1st mRNA Flu Shot, From Moderna. NBC News . August 6, 2026.
-
Who Needs a Flu Vaccine. Centers for Disease Control and Prevention . September 18, 2025.
Meet Our Experts
See Our Editorial Policy Meet Our Health Expert Network
Tom Gavin
Fact-Checker
Tom Gavin joined Everyday Health as copy chief in 2022 after a lengthy stint as a freelance copy editor. He has a bachelor's degree in psychology from College of the Holy Cross.
Pri...
Becky Upham
Author
Becky Upham has worked throughout the health and wellness world for over 25 years. She's been a race director, a team recruiter for the Leukemia and Lymphoma Society, a salesperson...
