At Othello Station Pharmacy in South Seattle, a familiar fall scene—pharmacist Ramla Abdi giving Greg McMurtry Jr. a flu shot—takes on a different meaning this year. Washington state is beginning to roll out mFlusiva, the first seasonal flu vaccine in the United States based on messenger RNA. The Moderna vaccine is authorized for people 50 and older, but its availability will vary: The state has already designated it as a preferred option for older adults, while it is not yet included in the free vaccine program for uninsured adults.
The U.S. Food and Drug Administration approved mFlusiva on Aug. 5, just as pharmacies and clinics were beginning to prepare for the fall vaccination campaign. The new vaccine is designed to protect against three flu strains: two type A viruses and one type B virus. It is the first licensed flu vaccine in the country to use mRNA technology, which millions of Americans became familiar with through COVID-19 vaccines.
Conventional vaccines are most often made by growing the virus in chicken eggs and then inactivating it. This is a proven approach, but it takes time, and the growing process can slightly alter the viral protein that the immune system is supposed to learn to recognize. mFlusiva contains instructions—mRNA packaged in lipid particles—that temporarily direct cells to produce the necessary viral protein. This approach does not depend on eggs and could potentially allow the vaccine’s composition to be updated more quickly as the constantly evolving flu virus changes.
There are concrete reasons for interest in the vaccine, although they do not justify calling it a miracle treatment. In an international Phase 3 study involving 40,805 people over 50, mFlusiva was 26.6% more effective than a standard-dose conventional vaccine at preventing laboratory-confirmed influenza-like illness. But the comparison was with a standard shot, not with enhanced vaccines that have long been recommended for older adults.
This is where an important qualification begins. For people ages 50 to 64, the vaccine received standard approval. For those 65 and older, it was authorized through an accelerated process: Federal regulators considered the immune-response data encouraging but required the manufacturer to conduct an additional comparative study against one of the enhanced vaccines already preferred for this age group. Doctors and patients have a new option, but not a final answer to whether it outperforms the best existing choices for the oldest adults.
The Washington State Department of Health nevertheless included mFlusiva among its preferred flu vaccines for people 65 and older, alongside Fluzone High-Dose, Fluad and Flublok. For everyone else, the principle remains the same: Annual vaccination is recommended for everyone 6 months and older unless there is a medical contraindication. Deborah Fuller, a professor of microbiology at the University of Washington, called the new technology a significant step forward, but emphasized a simpler truth: An available vaccine given on time is better than waiting for the perfect one.
The path from a regulatory decision to the counter of a particular pharmacy, however, has been uneven. In August, the state told health care providers that mFlusiva was expected to become commercially available during the current season, but it was not yet included in the Washington Adult Vaccine Program, which supplies participating clinics with free vaccines for uninsured adults. Even where the vaccine can be ordered, availability depends on supplies and on decisions by individual pharmacy chains, clinics and insurance plans.
Federal policy adds another layer of uncertainty. The Centers for Disease Control and Prevention kept its existing flu recommendations for the 2026–27 season and did not issue separate guidance on mFlusiva; the work of the Advisory Committee on Immunization Practices has been affected by legal disputes surrounding reforms to federal vaccine policy. Washington state, by contrast, chose not to wait: The new mRNA vaccine is already included in its recommendations. For someone visiting a pharmacy in the fall, that means a practical choice best discussed with a doctor or pharmacist—not a reason to postpone protection until bureaucracy has fully caught up with science.
Based on: Questions remain around WA rollout of new flu vaccine