EU selects seasonal flu vaccine strains for 2026/2027

Written by Gary Finnegan | 14 Apr 2026 | Infectious Diseases

The EU’s drug regulator, the European Medicines Agency (EMA), has issued recommendations for the influenza virus strains that vaccine manufacturers should include from autumn 2026.

Every year, EMA issues EU recommendations for the composition of seasonal influenza vaccines on the basis of observations by the World Health Organization (WHO), which are informed by regular monitoring activities on the prevalence and characteristics of different influenza viruses worldwide.

Manufacturers of live-attenuated vaccines or egg-based vaccines should include these three virus strains for the 2026/2027 season:

an A/Missouri/11/2025 (H1N1)pdm09-like virus;
an A/Darwin/1454/2025 (H3N2)-like virus;
a B/Tokyo/EIS13-175/2025 (B/Victoria lineage)-like virus.

Manufacturers of cell-based vaccines should include these three virus strains for the 2026/2027 season:

an A/Missouri/11/2025 (H1N1)pdm09-like virus;
an A/Darwin/1415/2025 (H3N2)-like virus;
a B/Pennsylvania/14/2025 (B/Victoria lineage)-like virus.

Previously, most authorised influenza vaccines were formulated to protect against the four main strains of influenza responsible for seasonal flu, including the strain known as B/Yamagata.

However, since B/Yamagata has not been detected in circulation since March 2020, it is considered to no longer pose a threat to public health. As a result, there is no EU recommendation for a B/Yamagata strain in seasonal influenza vaccines for the 2026/2027 influenza season, which is in line with the respective WHO recommendation regarding the composition of vaccines for 2026/2027.
In case quadrivalent vaccines are still required (e.g. in regions where the transition to trivalent vaccines has not been finalised yet), vaccine manufacturers of inactivated vaccines can consider producing a quadrivalent vaccine containing two influenza B virus strains for the 2026/2027 season. For these vaccines it is proposed to follow WHO recommendations from previous years for the B/Yamagata strain, i.e. a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

Influenza viruses continuously change and evolve. The periodic replacement of the virus strains contained in influenza vaccines is therefore necessary to keep the vaccines effective.