You may have seen advertisements for a brand-new flu vaccine manufactured by Moderna called MFLUSIVA (“em-floo-SEE-vah”), the first mRNA flu shot, made with the same type of technology used in some COVID-19 vaccines.
Before you roll up your sleeve, here’s why we’re not recommending this shot to our patients this season.
The Short Version
Newer doesn’t automatically mean better. For the flu, we already have excellent, well-studied vaccines that are a better choice for most of our patients, especially those 65 and older. Right now, no studies show MFLUSIVA protects you better than the vaccines we already use, and it tends to cause more side effects.
We’re sticking with what’s proven.
What We Already Use, and Why It Works
For adults 65 and older, flu can be serious, even life-threatening. National guidelines recommend one of three “stronger” flu vaccines for this age group:
- High-dose flu vaccine (Fluzone High-Dose)
- Recombinant flu vaccine (Flublok)
- Adjuvanted flu vaccine (Fluad)
These vaccines have years of real-world data behind them showing they reduce flu illness and flu-related hospital stays in older adults. Our practice prefers Flublok (recombinant) (see our latest vaccine update).
Where MFLUSIVA Falls Short
Moderna’s clinical trials show MFLUSIVA works better than a standard (basic) flu shot. But no one has tested it head-to-head in a real-world study against the stronger vaccines we use.
No clinical evidence shows it prevents flu illness, hospital stays, or deaths any better than Flublok. What exists so far are lab tests of antibody levels, a useful clue but not proof patients stay healthier.
The mRNA flu platform tends to cause more sore arms, fatigue, headache, muscle aches, chills, and fever than the vaccines we use. One major independent review for the American College of Physicians found more serious side effects with mRNA flu vaccines compared to the available high-dose vaccine options.
Think back to how you felt after your mRNA COVID-19 shots: the sore arm, tiredness, achiness, headache, or fever most people experienced in the day or two afterward. MFLUSIVA uses the same type of technology and tends to cause the same kind of reaction. For older adults, the trade-off matters: more discomfort with no proven added benefit isn’t a good deal.
The FDA approved MFLUSIVA for ages 50 and older only, and no approved mRNA flu shot exists for children. Pfizer tested a different mRNA flu vaccine in people over 65, and it didn’t work well enough to earn approval.
Even the FDA is waiting for more proof. When regulators approved MFLUSIVA, they required the company to run one more study to show whether MFLUSIVA protects older adults better than the stronger vaccines. The requirement tells you the question is still open.
What We Recommend
Get your flu shot. This isn’t a message to skip vaccination. Flu is dangerous, and vaccination is one of the best things you can do for your health.
Choose Flublok (recombinant), which we offer here.
If a pharmacist offers you MFLUSIVA, it’s reasonable to say, “My doctor recommends the Flublok (recombinant) vaccine this year.”
Have questions? Call the office. We’re happy to help you choose the right shot.
We’ll keep watching the research closely. If strong new evidence shows MFLUSIVA is better, we’ll update our advice. Until then, we’re recommending the vaccines with the strongest track record for keeping you safe.
What This Message Is (and Isn’t)
This blog post reflects our practice’s current vaccine recommendation, based on today’s evidence. It’s NOT a safety warning about mRNA technology, and it’s NOT a reason to avoid flu vaccination.
MFLUSIVA is an FDA-approved vaccine and an acceptable option under national guidelines; our recommendation favors the vaccines with the longest proven track record in older adults. At Banner Peak Health, we’ll revisit this guidance as new data becomes available.
