Protective immunity elicited by a pseudotyped baculovirus-mediated bivalent H5N1 influenza vaccine

► BV-HAs induce enhanced humoral and cellular immunity in a mouse model. ► BV-HAs conferred 100% protection against several strains of H5N1 viruses. ► The effective immunizing dose of BV-HAs was very low compared with mono-HA-based baculovirus. ► Recombinant baculovirus exhibited robust adjuvant efficiency in vivo without pre-existing antibody.