FDA Approves Moderna mRNA Flu Vaccine as Canada Reviews Application
The U.S. Food and Drug Administration has approved Moderna’s first mRNA-based influenza vaccine, MFlusiva, for adults aged 50 and older, reversing an earlier decision not to review the application. The vaccine could become available in the United States next year. Health Canada is conducting a separate review, and the FDA’s decision does not determine the Canadian outcome.
The approval draws on a late-stage trial involving more than 40,000 adults in the target age group. Moderna reported that the shot was 26.6 per cent more effective than existing standard-dose flu vaccines. The FDA granted traditional approval for adults aged 50 to 64 and accelerated approval for people 65 and older, subject to a further study confirming benefits in that group.
Canadian health specialists said the vaccine could offer additional protection for older adults, people with underlying conditions and immunocompromised patients. They also noted that improved effectiveness could reduce influenza-related illness and pressure on hospitals. Influenza causes thousands of deaths in Canada and tens of thousands in the United States annually, particularly affecting vulnerable populations.
Unlike many conventional flu vaccines, which are grown in chicken eggs and formulated months before flu season, mRNA vaccines provide cells with instructions to produce a harmless viral protein that trains the immune system. The technology may allow manufacturers to update and produce vaccines more quickly as circulating strains become clearer.
The decision comes amid broader debate over vaccine oversight in the United States. Moderna’s application was initially refused in February before being accepted after revisions. The company also withdrew a proposed combined COVID-19 and flu vaccine in 2025 after regulators requested more evidence. In Canada, regulators will independently assess MFlusiva’s safety, effectiveness and manufacturing data before deciding whether to authorize it, while public-health experts continue monitoring its potential role in seasonal influenza prevention and disease control.