Influenza vaccine composition changes for 2026/2027 season

The National Institute of Public Health (SZÚ) has released recommendations for the 2026/2027 influenza season, noting that all three viral strains in the trivalent vaccine have changed compared to last year. The new composition, aligned with World Health Organization guidelines, includes two Type A variants (A/Missouri/11/2025 and A/Darwin/1454/2025) and one Type B variant (B/Tokyo/EIS13-175/2025). Experts suggest October and November as the ideal months for vaccination.

However, the Czech Vaccinology Society has warned of potential delays in vaccine availability across Europe due to manufacturing complexities. These complications stem from the significant change in vaccine composition and delays in identifying the candidate B virus strain, which slowed the delivery of reference strains to manufacturers.

Specific supply timelines have been noted for certain products in the Czech Republic. Sanofi’s high-dose vaccine, Efluelda, is expected to arrive in stages starting in September and October, while the standard Vaxigrip vaccine is anticipated to be available in early November. Despite these delays, experts do not expect the overall vaccination season to be fundamentally disrupted.