The FDA has approved the first flu vaccine made with mRNA technology. It’s called mFLUSIVA, it’s made by Moderna and approved for adults 50 and older. Moderna began shipping doses this fall, but availability may vary by pharmacy.
If you are in that age group, you may be wondering how it differs from the flu shot you usually get and whether to ask for it. The mRNA flu vaccine is a new option, not a replacement. Other flu vaccines remain available, and getting vaccinated is more important than waiting for a particular type.
How Is It Different From a Regular Flu Shot?
Most traditional flu vaccines use inactivated, or killed, flu virus that is grown in eggs or cells. mFLUSIVA works differently. It uses mRNA, or messenger RNA, a small piece of genetic code.
The code tells your cells to make a harmless piece of flu virus protein. Your immune system learns to recognize that protein and is ready to respond if you are exposed to the flu. The mRNA breaks down after it delivers its instructions. It does not enter the cell’s nucleus or change your DNA.
This is the same technology used in the COVID-19 vaccines, but mFLUSIVA does not protect against COVID-19. Because mRNA vaccines use genetic instructions to help the body recognize a virus, the technology may also make it easier to update vaccines as flu strains change each year.
Who Can Get It?
Adults 50 and older can get the mRNA flu vaccine. It’s not approved for people under 50, who can still get a traditional flu shot made for their age.
There is one difference between age groups. For ages 50 to 64, the FDA gave full approval. For ages 65 and older, the approval is “accelerated,” based on immune-response data rather than a trial showing that the vaccine prevents flu illness in this age group. Moderna must run another study to confirm that it protects older adults from illness.
For adults 65 and older, the CDC recommends higher-dose, adjuvanted or recombinant flu vaccines over standard-dose flu vaccines. Although a separate study found that a Moderna mRNA flu vaccine produced a stronger immune response than a standard dose flu vaccine, researchers have not yet established whether mFLUSIVA prevents more flu illnesses than these enhanced vaccines.
See the CDC’s current flu vaccine recommendations for more information about vaccine options for older adults.
How Well Does It Work?
In a trial of about 40,000 adults ages 50 and older across 11 countries, mFLUSIVA reduced the risk of getting the flu by 26.6 percent compared with a standard-dose flu shot. Researchers confirmed flu cases through laboratory testing during the 2024–25 flu season.
This means the mRNA vaccine provided better protection in the study, not that it reduced every participant’s chance of getting the flu by 26.6 percentage points.
Is It Safe? What Are the Side Effects?
Clinical trials did not identify a new serious safety signal. However, common short-term side effects were more frequent with mFLUSIVA than with the standard-dose flu shot. They include a sore arm, tiredness, headache and muscle aches. Some people also experience chills, fever or nausea. Most reactions were mild to moderate and lasted about two days.
Do not get mFLUSIVA if you have had a severe allergic reaction to the vaccine or one of its ingredients. Tell your provider if you had Guillain-Barré syndrome within six weeks of a previous flu vaccination. If you have a weakened immune system, your response to the vaccine may be lower. For additional safety information, see the FDA’s mFLUSIVA product information.
Where Can I Get It, and Will Insurance Cover It?
Availability may vary, so call your pharmacy or health care provider before making an appointment. Insurance coverage may vary, so check with your insurer and vaccination provider before your appointment.
Should I Ask for It?
That depends on your age, your health and what is available to you. A traditional flu shot is a good choice if you prefer a vaccine with a longer track record. For adults 65 and older, it is worth discussing with your provider how mFLUSIVA compares with the enhanced flu vaccines recommended for your age group. Whichever you choose, don’t delay getting vaccinated while you wait for a particular type. Protection takes about two weeks to build.
Bottom Line
mFLUSIVA is a new flu vaccine option for adults 50 and older. In a large trial, it provided better protection against lab-confirmed flu-like illness than a standard-dose flu shot, but common short-term side effects were more frequent. Its approval for adults 65 and older is based on immune-response data, and more research is needed to confirm its ability to prevent flu illness in this age group. Talk with your provider or pharmacist about which flu vaccine is right for you.
