MFlusiva is an mRNA vaccine used to prevent the flu (influenza). It's approved for adults 50 years and older. MFlusiva is given as a single injection into the shoulder muscle by a trained healthcare professional. It can be given once each flu season. Common side effects are injection site pain, muscle pain, tiredness, and headache.
MFlusiva is an mRNA vaccine. It contains lab-made mRNA (genetic information). This piece of mRNA teaches your body to make a protein found on the influenza virus.
Your immune system recognizes this protein as something that doesn't belong in your body. This causes your immune system to make antibodies and other defenses against it.
Afterwards, your immune system remembers what this flu protein looks like. If you're exposed to a matching flu strain later, your immune system can respond faster.
| Common Brands | Mflusiva |
|---|---|
| Drug Class | mRNA vaccine |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | No lower-cost generic available |
| Availability | Prescription only |
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Contact your healthcare provider immediately if you experience any of the following.
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
MFlusiva can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Serious allergic reactions, such as anaphylaxis, can happen after mFlusiva is given. This reaction can cause hives, swelling of your face or throat, trouble breathing, a fast heartbeat, dizziness, or weakness.
Your vaccinator might ask you to stay for a short time after you get mFlusiva so they can watch for allergic reactions. The vaccination site should have treatment available in case one happens.
Tell your vaccinator right away if you notice any symptoms while you're there. If symptoms start after you leave, get medical help right away.
It's not clear whether flu vaccines, including mFlusiva, cause Guillain-Barré syndrome (GBS). If there is an increased risk, it's very small. GBS is a rare condition where the immune system attacks the nerves. It can cause tingling, muscle weakness, or trouble walking. More serious cases can cause trouble swallowing or breathing or an irregular heart rate.
Tell your prescriber if you've had GBS within 6 weeks of a previous flu vaccine. They can help decide if mFlusiva is right for you. Get medical help right away if you have new or quickly worsening weakness, tingling, or trouble breathing.
Fainting can happen after you get an injectable vaccine, including mFlusiva. You might feel lightheaded, dizzy, or suddenly lose consciousness. If you faint, you could get hurt in a fall.
Tell your vaccinator if you've fainted after any injections before. They can help you sit or lie down and watch you after they give you the mFlusiva shot. Get help right away if you get hurt after fainting or if you don't quickly recover.
If you have a weakened immune system, your immune system might not respond as strongly to mFlusiva. This means you might have less protection against the flu after vaccination.
Tell your vaccinator about your health conditions and medications before getting mFlusiva. Certain health conditions, such as HIV or cancer, can weaken your immune system. Some medications, like high-dose steroids or transplant medications, can have a similar effect. Your care team can talk with you about other ways to help protect yourself from the flu.
Syringe| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 0.38ml of | 1 syringe | $150.43 | $150.43 |
The typical dose is 1 injection (0.38 mL) given into a muscle by a trained healthcare professional. It's given as a single dose once each flu season.
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Yes. The FDA approved MFlusiva, Moderna's mRNA flu vaccine, in August 2026. It has a full approval for adults ages 50 to 64 years old. For adults age 65 and older, it received accelerated approval. More research is needed to confirm its benefits in this age group. MFlusiva isn't approved for people younger than 50.
MFlusiva is expected to be available in the U.S. for the 2026–2027 flu season. Call your local pharmacy or vaccination clinic first if you want to be sure it's available.
MFlusiva is currently available in certain U.S. retail pharmacies. This can include some CVS and Walgreens pharmacies. You can check the Moderna vaccine locator to find where MFlusiva is available near you. You can also ask your local pharmacy if it has MFlusiva in stock and if a pharmacist can administer it.
Yes. The 2026–2027 formula of MFlusiva is trivalent. This means it covers three flu strains: two influenza A strains and one influenza B strain.
No, you can't get the flu from MFlusiva. It's an mRNA vaccine and doesn't contain the live flu virus, so it can't cause a flu infection. It takes about 2 weeks for your body to build protection, so you could still get the flu during this time. You might also have side effects like tiredness, headache, muscle aches, or chills. These can feel like flu symptoms, but they aren't the flu.
No, MFlusiva shouldn't be given during pregnancy because there isn't enough information to know if it's safe. Talk to a healthcare professional or obstetrician-gyncelogist (OB-GYN), or vaccinator about flu vaccine options during pregnancy.
