First mRNA Flu Shot Approved in US as Moderna Reaches Major Milestone

The U.S. Food and Drug Administration (FDA) has approved Moderna’s seasonal influenza vaccine, making it the first mRNA-based flu vaccine to receive regulatory approval in the United States and marking another milestone for the messenger RNA technology that gained global prominence during the COVID-19 pandemic.

The newly approved vaccine, marketed as mNEXFLU, is authorized for adults aged 50 years and older, a group considered to be at higher risk of serious influenza-related complications. The approval follows positive results from a large Phase 3 clinical trial involving more than 40,000 participants, where the vaccine demonstrated strong immune responses against all four influenza strains included in the seasonal formulation.

Moderna said the vaccine met its primary objectives by generating superior antibody responses compared with an existing licensed standard-dose influenza vaccine in adults aged 50 to 64, while showing non-inferior immune responses in adults aged 65 and above. The company believes the mRNA platform could significantly improve the effectiveness of annual flu vaccines by allowing manufacturers to update vaccine strains more rapidly as influenza viruses evolve.

Unlike traditional flu vaccines, which are typically produced using chicken eggs or cell-based manufacturing processes that can take several months, mRNA vaccines are designed using genetic instructions that enable the body’s cells to produce harmless viral proteins, prompting an immune response. This technology offers greater flexibility and faster production timelines, potentially improving the match between vaccines and circulating influenza strains.

The FDA’s decision represents an important victory for Moderna as the biotechnology company seeks to diversify its product portfolio beyond COVID-19 vaccines. Sales of coronavirus vaccines have declined sharply worldwide since the height of the pandemic, prompting the company to invest heavily in developing vaccines targeting influenza, respiratory syncytial virus (RSV), and other infectious diseases.

Moderna Chief Executive Stéphane Bancel described the approval as a major step forward for public health and the company’s broader respiratory vaccine strategy. He said the mRNA platform has the potential to transform how seasonal influenza vaccines are developed and delivered, allowing faster adaptation to changing virus strains while maintaining high levels of effectiveness.

Health experts welcomed the approval but cautioned that real-world effectiveness will continue to be monitored during upcoming flu seasons. Influenza remains a significant public health challenge, causing millions of illnesses and hundreds of thousands of hospitalizations globally each year. In the United States alone, seasonal flu contributes to thousands of deaths annually, particularly among older adults and people with underlying medical conditions.

The approval also intensifies competition in the influenza vaccine market, where manufacturers such as Sanofi, GSK, CSL Seqirus and Pfizer are developing next-generation vaccines aimed at improving protection against rapidly mutating influenza viruses. Moderna is also conducting studies on a combined COVID-19 and influenza vaccine that could eventually reduce the number of annual vaccinations required.

Public health officials say the arrival of the first approved mRNA influenza vaccine could reshape seasonal vaccination campaigns in the years ahead, offering a new tool to combat one of the world’s most persistent respiratory diseases while opening the door for further innovation in vaccine technology.