[Trends and perspectives in development of influenza vaccines]

Currently licensed influenza vaccines in Japan are split-virus vaccine for seasonal influenza and alum-adjuvanted whole-virion vaccine for higly pathogenic avian H5N1 influenza, respectively. There are many challenges to improve the efficacy, safety and productivity of influenza vaccine. Prompt supply of vaccine is required for pandemic use and cell culture-based vaccine provides a useful production system because of the flexibility of scale-up production. Development of potent adjuvants for parenteral and intranasal administration enhances the immunogenicity and efficacy of influenza vaccine. Vaccines inducing nasal antibody have a potency to elicit broad protective immune response against different subtypes and antigenically distinguishable viruses. More effective and safer influenza vaccine in a single formulation is desirable for both seasonal and pandemic use.