Cell culture (Vero cell) derived whole-virus non-adjuvanted H5N1 influenza vaccine induces long-lasting cross-reactive memory immune response: Homologous or heterologous booster response following two dose or single dose priming

► Non-adjuvanted whole-virus H5N1 vaccine induces long-lasting memory response. ► Consistently strong booster responses following different prime-boost schedules. ► Similarly strong responses to heterologous booster after one or two dose priming. ► H5N1 vaccine is well tolerated after priming and booster vaccinations.