The present invention discloses recombinant adenovirus and methods of administration of the virus to a host inorder to elicit an immune response against various pathogens in the host. Specifically, a vaccination method to enhance immunity of the host to the pathogen is disclosed herein. Such a method comprises recombinant adenoviruses expressing viral antigens, where the recombinant adenoviruses are derived from different serotypes or subtypes. Alternatively, the adenoviruses in such a method can also be constructed by modifying the backbone of one of the adenoviruses (e.g. the knob, shaft or fiber regions) so that it is of a serotype that is different from the corresponding region(s) in the backbone of the other recombinant adenovirus.