US FDA advisers recommend flu vaccine strains for 2027 Southern Hemisphere season
XLV•An FDA advisory committee unanimously recommended that manufacturers include H1N1, H3N2 and influenza B strains in egg-based trivalent flu vaccines for the 2027 Southern Hemisphere season.
1. Committee recommendation
All nine voting members of the Vaccines and Related Biological Products Advisory Committee backed the strain recommendations. The committee's recommendations are non-binding, though the FDA generally follows them.
2. US flu activity
The CDC said seasonal influenza activity is low this year, with 31,363 laboratory-confirmed influenza-associated hospitalizations reported as of September 18. It estimates the 2025-26 season resulted in 32 million to 57 million illnesses, based on preliminary data through May 23.
3. Vaccine production
Manufacturers project they will produce as many as 135 million flu vaccine doses for the US market for the 2026-2027 season, the CDC said. Sanofi and CSL Seqirus are approved to produce Southern Hemisphere formulations of Fluzone and Afluria, respectively, in the US.
