The present invention relates to immunogenic compositions and vaccines of flavivirus. In particular, the present invention relates to improved Dengue vaccines and the design and making of such vaccines that enhance immunogenicity of the vaccine. The vaccines and immunogenic compositions of the present invention relate to mixed head bivalent flagellin-dengue antigen fusion proteins which can be combined with other bivalent dengue antigen fusion proteins or monovalent dengue antigen fusion proteins to produce multivalent vaccine including tetravalent vaccines.