The FDA approved Moderna’s influenza vaccine, mFLUSIVA, for adults ages 50 years and older, giving the United States its first mRNA-based seasonal flu shot. The decision also included accelerated approval for adults ages 65 years and older.
Moderna mFLUSIVA Trial Data
The approval rested on a phase 3 clinical trial involving more than 40,000 adults ages 50 and older across 11 countries. Around half received mFLUSIVA and the rest got a standard-dose licensed flu vaccine. Researchers said mFLUSIVA was superior to the standard-dose shot in preventing flu-like illness confirmed by RT-PCR lab tests.
Moderna expects mFLUSIVA to be available in the United States for the 2026 to 2027 respiratory virus season. That timing matters for adults 50 and older who are deciding whether a new flu prevention option will be part of their next seasonal vaccination plan.
Dung Trinh and David Cutler
Dung Trinh, an internist and Chief Medical Officer of Healthy Brain Clinic, called the approval “an important addition to our influenza prevention toolkit, particularly because adults over 50 begin to experience a progressively higher risk of serious complications from influenza.” He also said, “This is also a significant scientific milestone because it is the first mRNA-based seasonal influenza vaccine approved in the United States, showing that mRNA technology can be applied beyond COVID-19.”
David Cutler, a board certified family medicine physician at Providence Saint John’s Health Center, said, “My overall view is cautiously favorable. The FDA approval of Moderna’s mFLUSIVA (mRNA-1010) is scientifically interesting and potentially important, but I would not interpret it as proof that the mRNA vaccine is necessarily the best flu vaccine for every person over 50,”
Adults 65 and Older
Cutler said the FDA decision gives people ages 50 to 64 traditional full approval, while adults ages 65 and older received accelerated approval with a requirement for additional post-approval evidence confirming clinical effectiveness. He said, “That distinction matters,” because people 65 and older are the group in which the question of whether the vaccine actually prevents hospitalization, pneumonia, and death matters most.
That leaves the older group with a narrower evidentiary path. The approval followed a clinical trial involving over 2,900 adults in the United States that measured immune response to mFLUSIVA against a high dose inactivated flu shot, while the post-approval evidence requirement keeps the focus on whether the vaccine delivers real-world protection in that age group.
The backdrop is a flu season that the Centers for Disease Control and Prevention estimated produced about 45,000 flu-related deaths in the United States in 2024 to 2025, with vaccination estimated to have prevented around 12,000 deaths. For adults 50 and older, the immediate question is whether Moderna’s new vaccine becomes a routine option when the 2026 to 2027 respiratory virus season arrives.
