English
The United States now has its first flu vaccine built on mRNA technology. Moderna’s mFlusiva uses the same messenger RNA platform behind the company’s widely used Covid-19 shots. However, the vaccine is not available to everyone. The FDA approved mFlusiva only for adults aged 50 and older, and eligibility rules are already creating confusion at pharmacies across the country.
Who Can Receive the mRNA Flu Vaccine
Only adults aged 50 and older qualify for mFlusiva this flu season. “If you have not celebrated your 50th birthday, this vaccine should be of no interest to you,” said Emlah Tubuo, an independent pharmacist in Ohio. People under 50 can still receive one of the many traditional flu vaccines approved for their age group.
Stay connected to every major update — subscribe and follow us on the PhoenixQ website and across our social media platforms.
The FDA granted standard approval for adults aged 50 to 64. For adults 65 and older, the agency issued accelerated approval. As a condition of that approval, Moderna must conduct an additional clinical trial in that older age group.
That requirement stems from a controversy that nearly blocked the vaccine entirely. In its large clinical trial, Moderna compared mFlusiva against a standard-dose flu shot in adults 65 and older. The CDC, however, recommends a high-dose flu shot for that age group. The FDA initially refused to review Moderna’s application over that issue. The agency later reversed course and agreed to require a post-approval trial instead. In June, the FDA’s independent vaccine advisory panel unanimously recommended approval for older adults.
How mFlusiva Differs from Traditional Flu Shots
The core difference lies in how each vaccine trains the immune system. Most traditional flu shots use a deactivated form of the influenza virus, often grown in eggs, to trigger an immune response. mFlusiva, by contrast, delivers a small piece of genetic code that instructs the body to recognize and fight the flu virus. After the vaccine does its job, the mRNA breaks down and leaves the body entirely.
“It’s like a temporary instruction to your immune system to alert your body’s natural defense to recognize influenza,” Tubuo said. As with other flu vaccines, it takes about two weeks after vaccination to build full protection.
One common point of confusion, according to Brigid Groves of the American Pharmacists Association, is whether mFlusiva also protects against Covid-19. It does not. The vaccine targets influenza only. It is also separate from Moderna’s combination Covid and flu vaccine, which the European Union approved in April. Like traditional flu vaccines this season, mFlusiva is a trivalent vaccine. It targets two influenza A strains and one influenza B strain.
Another key advantage is production speed. Traditional flu vaccines can take up to six months to manufacture. Moderna says mFlusiva can be ready in two to three months. Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center, said that shorter timeline allows scientists to wait longer before selecting which strains to target. As a result, they can make better-informed choices about which strains are most likely to circulate.
Safety, Effectiveness and Clinical Trial Results
A Phase 3 clinical trial published in the New England Journal of Medicine in May found mFlusiva to be about 27% more effective than a standard-dose flu shot. More than 40,000 adults aged 50 and older across 11 countries, including the United States, took part in the trial.
FDA reviewers found no serious safety problems with the vaccine. Side effects such as injection-site pain, fatigue and headaches occurred more often in the mFlusiva group than in the standard vaccine group. However, those effects remained mild to moderate. Schaffner suggested the higher rate of side effects may reflect “the vigor with which the immune system responds to the vaccine.”
Insurance Coverage, Cost and Availability
mFlusiva is reaching pharmacies without a formal recommendation from the CDC or its vaccine advisory committee. That step is typically required before insurers must cover vaccines at no cost. A spokesperson for AHIP, a health insurer trade group, said most private insurers are expected to cover the vaccine. Meanwhile, vaccine policy expert Dorit Reiss of University of California Law San Francisco noted that Medicare is required to fully cover FDA-approved seasonal flu shots. However, Reiss said it remains unclear how broadly Medicaid will cover mFlusiva, since that program generally requires a formal CDC advisory committee recommendation first.
Without insurance, the Centers for Medicare and Medicaid Services lists mFlusiva at around $171 per dose. Depending on the pharmacy, GoodRx data shows the price could be as low as $154.
Moderna has begun shipping doses across the country. CVS Health confirmed that mFlusiva is currently available at its U.S. pharmacies. Walgreens said it expects shipments to arrive soon, though supplies will be limited this season. Tubuo noted that demand remains low for now, adding that most people typically do not seek flu vaccination until October. The CDC recommends getting vaccinated by the end of that month.
