Clinical development of a Vero cell culture-derived seasonal influenza vaccine

► Vero-derived seasonal influenza vaccine is safe and immunogenic in young and older adults. ► All EU and US immunological licensing thresholds comfortably met for all vaccine strains. ► Vaccine is highly efficacious in preventing culture-confirmed influenza infection. ► Vaccine efficacy against matched strains was 78.5%, against all strains 71.5%. ► HI titer correlates with protection, no additional benefit at titers >1:30.