Polynucleotides encoding hepatitis B virus (HBV) core antigen and polymerase antigen, and related combinations are described. Also described are vectors, such as DNA plasmids or viral vectors, expressing the HBV core and polymerase antigens, and immunogenic compositions containing the expression vectors. Methods of inducing an immune response against HBV or treating a HBV-induced disease, particularly in individuals having chronic HBV infection, using the immunogenic compositions are also described.