[Intranasal application of inactivated influenza virus vaccines]

Recent concept on the common mucosal immune system gives new direction of influenza vaccine development-mucosal vaccine. Vaccines have to be administered over the mucosal surface (in case of influenza vaccine, intranasal route may be the most suited route) to assure mucosal immunity which is the first hand armament against influenza virus. This article reviews our work on intranasal administration of inactivated influenza virus HA vaccines. Since influenza vaccines are usually given to people who has some degree of immunity due to past infection or immunization, vaccines which have booster effect are preferable. In this context, intranasally administered inactivated influenza HA vaccine was more immunogenic than cold adapted reassortant live influenza virus vaccine, another candidate mucosal influenza virus vaccine, which is now under investigation in the United States.