Seattle—A new messenger RNA (mRNA) flu vaccine, branded mFLUSIVA, has been cleared for use among adults 50 years of age and older. UW Medicine says the product delivers nearly a 30% boost in effectiveness compared with the standard inactivated influenza vaccine, a difference that could be significant for a demographic that faces higher rates of hospitalization and death from the virus.
Effectiveness and Target Population
Dr. Deborah Fuller of UW Medicine explained that people over 50 experience “immunosenescence,” a gradual decline in immune function that makes traditional vaccines less responsive. The mRNA platform, the same technology used in COVID‑19 vaccines, enables the body to generate antibodies that recognize a wider array of influenza strains and maintain protection for a longer period.
According to UW Medicine, the new shot’s nearly 30% greater efficacy is measured against the traditional flu vaccine in clinical trials involving older adults. The same trials also reported stronger side effects, including fatigue, muscle aches and joint pain, relative to the conventional shot.
Washington state recorded 253 flu‑related deaths in the most recent season, and 508 deaths in the prior season (2024‑25). More than 91% of those fatalities occurred in people 50 and older, underscoring the heightened risk for this age group.
Availability, Coverage and Public Response
mFLUSIVA is being introduced through major pharmacy chains such as CVS and Walgreens, although not every local outlet will have the vaccine immediately. Dr. Fuller advises anyone in the eligible age range to consult a physician or pharmacist before receiving the shot, especially if they previously experienced a severe reaction to a COVID‑19 mRNA vaccine.
Coverage appears favorable for seniors: adults 65 and older are likely to have the vaccine reimbursed through Medicare plans. The extent of private‑insurance coverage for adults 50‑64 remains unclear, and KOMO News has reached out to Washington’s Office of the Insurance Commissioner for clarification.
Community members expressed a mix of personal experience and optimism. Seattle resident Bob Aristarco, who has contracted the flu several times, said, “I’ve had the flu a couple of times; you’re sick for 10 days. I don’t want that!” After recovering from COVID‑19, he and his wife intend to obtain flu shots at the start of each season. Similarly, Chuck Gould and his wife affirmed their commitment to annual flu vaccination, noting that “there’s always room for science to expand and improve and make things better.” Gould also remarked that current public discourse sometimes creates “more hysteria than needed” around vaccinations.
Last season, only 29.2% of eligible Washington residents received a flu vaccine, according to the state Department of Health. The introduction of an mRNA option may influence uptake, particularly among those seeking a vaccine that addresses the challenges of an aging immune system.
Dr. Fuller summed up the public‑health perspective: “Having a vaccine is better than not having a vaccine, and mRNA vaccines are safe, they are effective, they have been proven.” As flu season approaches, health officials hope the added efficacy of mFLUSIVA will translate into higher vaccination rates and fewer severe outcomes for Washington’s older adults.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
