Even though conventional vaccines have been relatively successful against influenza A infection, the ability of adenoviral vectors to rapidly generate a strong immune response may be useful to specific applications such as rapid immunization of health care workers in anticipation of a probable exposure to an emerging virulent pandemic virus such as H1N1-1918. In addition to strong antibody responses against the H5N1-H05 virus, both survival and cellular responses suggest that induction of an earlier T-cell response by the PAV3-may complement the developing antibody response to improve protection against H5N1 challenge and contribute directly towards lower viral load. Although the influenza glycoproteins have high antigenic variation, the generation of faster T-cell responses by a PAV3 vector against well-conserved influenza antigens may supplement a mismatched antibody response and may improve protection against a wider range of influenza viruses.