FDA Approves Moderna's First mRNA Flu Vaccine for Seniors

The approval covers mFlusiva, which targets four influenza strains and is the first messenger RNA-based flu shot cleared in the United States. Traditional flu vaccines are typically made by growing viruses in eggs or cell cultures, a process that can take up to six months. Moderna's mRNA platform instead uses genetic instructions to prompt cells to produce viral proteins, allowing production in two to three months.

In clinical trials, mFlusiva demonstrated a 27% lower rate of laboratory-confirmed flu illness compared to standard inactivated vaccines among adults 50 and older. The shot is expected to be available for the 2025-2026 flu season, with pricing and distribution details to be announced later.

The FDA's decision comes as public health officials seek to improve flu vaccine effectiveness, which has ranged from 19% to 54% in recent seasons depending on strain matching. mRNA technology allows manufacturers to update shots more quickly if circulating strains change, potentially offering better protection during mismatched seasons.

Moderna plans to submit data from additional studies to support approval for younger adults and children. The company is also developing combination vaccines that target both flu and COVID-19, which could simplify immunization schedules in the future.