A new influenza vaccine developed in Japan is sprayed into the nose. It takes advantage of mucosal immunity in the nose and mouth to stop infection. It has a low risk of side effects and can be used on infants and the elderly. Injected vaccines aim to stop an infection from worsening. They cannot prevent infection itself, but the nasal spray can. The nasal spray vaccine has completed all clinical trials and has the potential to be adapted for use against the new coronavirus.