The First mRNA Flu Vaccine Is Here: What You Need to Know
Flu is not a minor enemy. Preliminary CDC estimates suggest the 2025-2026 flu season resulted in approximately 390,000 hospitalizations and 24,000 flu-associated deaths in the United States. Against this backdrop, the first mRNA-based flu vaccine — Moderna's mFlusiva — has officially arrived at U.S. pharmacies, drawing widespread attention.
What Is mFlusiva?
mFlusiva is the first flu vaccine to use messenger RNA (mRNA) technology, the same platform used in Pfizer and Moderna's COVID-19 vaccines. Unlike traditional vaccines — which typically use inactivated viruses grown in eggs — mFlusiva uses a temporary sequence of genetic material to instruct the immune system. The mRNA decomposes after fulfilling its function and does not remain in the body.
Who Can Get It? What Is the Key Limitation?
The FDA has approved mFlusiva for adults aged 50 and older. People under 50 should continue to use traditional flu vaccines available for their group.
Notably, approval for adults aged 65 and older was marked by controversy. Moderna compared mFlusiva with a standard vaccine, although the CDC recommends a high-dose formula for that age group. The FDA demanded a new clinical trial after approval.
How Effective Is It?
- A Phase 3 study published in the New England Journal of Medicine enrolled more than 40,000 adults aged 50 and older
- Results showed mFlusiva was approximately 27% more effective than a standard flu vaccine at preventing laboratory-confirmed cases
- Like this year's seasonal vaccines, mFlusiva protects against three strains: two of influenza A and one of influenza B
- The vaccine protects against flu only — it does not replace COVID-19 vaccines
The Advantage of Faster Production
Moderna claims it can produce mFlusiva in two to three months, compared to approximately six months for a traditional vaccine. That shorter timeline could allow selecting target strains closer to the start of the season, potentially improving vaccine matching.
Confusion at Pharmacies
According to NBC News, pharmacies say the new vaccine is already causing confusion among some patients about who can get it. Experts recommend that people under 50 choose traditional flu vaccines, while those 50 and older can discuss with their doctor or pharmacist whether the mRNA flu vaccine is right for them.
What It Means for Public Health
The arrival of an mRNA flu vaccine marks a new era in flu prevention. Its faster production cycle and higher efficacy offer a new tool for tackling flu season. However, questions remain about the best option for those over 65, long-term safety data, and cost accessibility.
Want to manage your health better? The Xiaoshu Health App can sync with Apple Health to track relevant metrics, helping you record temperature, heart rate, sleep, and other data so you can monitor your body's response after vaccination.