The invention relates to a multi-HBV immunogen viral vector vaccine comprising: a viral vector comprising an immunogen expression cassette, wherein the expression of a protein encoded by the expression cassette is arranged to be driven by a promoter, wherein the immunogen expression cassette encodes: a) HBV Core; b) a modified HBV polymerase (Pmut), wherein the modification is a mutation to wild-type HBV polymerase to substantially remove polymerase function; c) HBV surface antigen (HbsAg); and d) an intergenic sequence that is arranged to cause expression of at least the HBV surface antigen (HbsAg) as a separate protein from the HBV core and the modified HBV polymerase (Pmut), wherein the intergenic sequence is downstream (3′;) of the sequences encoding the HBV core and the modified HBV polymerase (Pmut) and upstream (5′;) of the sequence encoding the HBV surface antigen (HbsAg); and related compositions, vaccination methods and methods of treatment or prophylaxis of HBV infection.