Is a More Effective Flu Vaccine on the Horizon?

Adults 50 and older could soon have another option for their annual influenza shot

Rachel Nania,

AARP

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Published April 03, 2026

conceptual 3D illustration showing a production line of blue-tinted vaccine vials on a curved silver conveyor belt

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Key takeaways

The FDA is reviewing the first mRNA flu vaccine for adults age 50 and older, which could offer stronger protection than traditional flu shots.
mRNA flu shots can be produced more quickly than traditional vaccines, allowing a closer match to circulating strains.
Annual flu vaccines are especially important for older adults, who are at higher risk of severe illness from influenza.

The U.S. Food and Drug Administration (FDA) is reviewing a new flu vaccine for adults age 50 and older. If approved, it would be the first influenza shot to use mRNA technology, and experts say it could offer individuals stronger protection against the common virus.

Each year the flu vaccine prevents millions of cases of illness — an estimated 10 million during the 2024–25 winter season, according to preliminary estimates — and thousands of deaths from flu, which disproportionally affects older adults. Even still, there’s room for improvement.

“Our current flu vaccines work, but they can be better,” says Andrew Pekosz, professor and vice chair of the W. Harry Feinstone Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health and codirector of the Johns Hopkins Center of Excellence in Influenza Research and Response.

To make the annual flu shot, experts meet every winter to review surveillance data and determine which influenza viruses are most likely to make people sick later that year. Then, manufacturers get to work to include these strains in the upcoming season’s vaccine.

The process takes several months, and sometimes, the result is a vaccine that no longer matches the flu viruses circulating in the community.

“But mRNA vaccines don’t need to take as long to manufacture as traditional vaccines. So instead of five to six months to make, they can take less than two months to manufacture,” says Gigi Gronvall, a professor in the department of environmental health and engineering at the Johns Hopkins Bloomberg School of Public Health.

That means researchers and companies can start working on them closer to the actual flu season. “This should lead to vaccines that are better matches for what flu viruses people are actually likely to encounter during the season,” Gronvall says.

What are mRNA vaccines?

Many people are familiar with mRNA, at least by name, from the development of the COVID-19 vaccines in 2020. There is also an mRNA vaccine for RSV (respiratory syncytial virus).

What makes mRNA vaccines different from other types of vaccines? First, it’s important to know that “all vaccines basically do the same thing,” Pekosz says. “They show your body something that is foreign, and they do it in a way that allows your immune system to recognize it and eliminate it.”

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The flu shots currently available do this by introducing an inactivated particle or protein from the flu virus to stimulate an immune response.

The mRNA flu vaccine, on the other hand, contains instructions for the body to make a protein — a harmless piece of the flu virus — that generates the same type of immune response, explains Dr. Steven Lawrence, a vaccine expert and professor of medicine in the division of infectious diseases at WashU Medicine in St. Louis. These instructions can be updated to match the flu strains circulating in the community.

What are the benefits of an mRNA vaccine?

The most important part of mRNA technology, Pekosz says, is how quickly you can make a vaccine once you know what you want to target. “It’s sort of like switching from a horse and buggy to a Corvette for travel. The mRNA technology still does the same basic thing, just a lot faster,” he says.

The faster manufacturing timeline not only allows the vaccine to be updated closer to the start of flu season, but it also positions researchers to respond more quickly to potential flu pandemics. Take, for instance, the 2009 H1N1 flu pandemic. By the time a vaccine for the virus was ready, the pandemic’s peak had already passed, Lawrence says.

“If we had that mRNA technology in 2009, we very likely could have had enough vaccine for the entire population before the peak hit and been able to administer it before the peak hit,” Lawrence says.

An mRNA flu vaccine would also “avoid some of the complications of egg-grown influenza vaccines,” Pekosz says. Most flu vaccines in the U.S. are made using chicken eggs, and “that process of growing influenza in eggs can sometimes introduce mutations that make those vaccines less effective at inducing responses to the current circulating vaccines.”

What’s more, “the very chickens that lay the eggs that make the vaccine could be wiped out” by future bird flu outbreaks, Lawrence says. “And so if you don’t have to rely on chickens, then you’ve also not only sped things up, but you’ve eliminated that as a potential way that maybe we’d have very limited capacity for vaccine production.”

Another plus: Pekosz says mRNA vaccines tend to generate a more robust immune response. In a phase 3 clinical trial, the Moderna mRNA influenza vaccine under FDA review elicited a superior immune response compared to the standard-dose flu vaccine.

“It works about 25 percent better in people 50 and over” than a standard-dose flu shot, Lawrence says. “It’s important because those are people who are at higher risk of getting really sick or dying from flu.”

It’s unclear how the mRNA vaccines compare with the high-dose flu shots recommended for adults 65 and older, but Moderna has said it will study this.

Misinformation and mRNA vaccines

Since their introduction about six years ago, mRNA vaccines have been a frequent target of misinformation. “And some of those falsehoods have, unfortunately, remained stuck in people's minds,” Gronvall says — such as the fear that mRNA vaccines get incorporated into a person’s DNA, or that they cause infertility or cancer.

These claims are not true, Gronvall stresses. In fact, scientists are studying mRNA vaccines for treating cancer.

Because mRNA vaccines generate a strong, robust immune response, Lawrence says, they can be more likely to cause side effects in some people, the most common being a sore arm, fatigue and feeling achy or feverish. “It’s the immune system revving up,” he says.

However, “many companies have now second or third generations of these mRNA vaccine platforms that actually have been designed to reduce some of those side effects and to make them a little bit more acceptable in the population,” Pekosz says.

What are flu shot options for older adults?

In a February news release, Moderna said pending review and FDA approval, its mRNA flu vaccine could be available for U.S. adults age 50 and older for the 2026–27 flu season. Most people are encouraged to get their annual flu vaccine in September or October, just ahead of the start of the season.

If the mRNA vaccine isn’t available this year — and there’s no guarantee it will be — experts recommend getting the one that is. Adults 65 and older, who are at higher risk of complications from influenza, should choose a high-dose or adjuvanted option.

“I want to be very clear that everyone should get a flu shot every year,” Gronvall says.

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