US FDA approves first mRNA flu shot from Moderna

The approval was based on data from a late-stage trial involving more than 40,000 adults aged 50 and older, which showed the shot was 26.6% more effective than a licensed standard-dose flu vaccine.

The company also submitted separate late-stage data showing the vaccine generated stronger antibody responses than Sanofi's high-dose flu vaccine in adults 65 and older.

MFlusiva would compete with flu vaccines from Sanofi SASY.PA, GSK GSK.L, CSL Seqirus CSL.AX, and AstraZeneca AZN.L.

Moderna's vaccine uses mRNA technology to prompt the body to produce influenza antigens and trigger an immune response, an approach that could potentially allow faster updates to match circulating strains.

In comparison, conventional flu shots are largely egg-based and contain viral proteins.