Efficacy of an AS03A-adjuvanted split H5N1 influenza vaccine against an antigenically distinct low pathogenic H5N1 virus in pigs

► Vaccine and challenge H5N1 strains showed only 85% aa homology in their HA1. ► Adjuvanted vaccine induced VN antibodies against the challenge virus in all pigs. ► Adjuvanted vaccine offered a robust virological protection against challenge. ► AS03A-adjuvanted H5N1 vaccine may offer a broader protection than generally assumed. ► The pig model of H5N1 influenza virus challenge can still be improved.