Abstract
Conventional influenza vaccine has been administered subcutaneously or intramuscularly, and the objective is focused on the prevention of becoming severe. On the other hand, in case the prevention of infection is emphasized, since the infectious route of influenza virus is mucosa, transmucosal (such as intranasal or oral) route is supposed to be promising. Intranasal route is particularly hopeful since the route is able to decrease the amount of vaccination because of the low risk for denaturation of antigen.