Immune response to combined live influenza virus vaccines administered intranasally.

The immune responses in volunteers vaccinated intranasally with a live influenza virus vaccine containing attenuated A and B strains have been studied. The hemagglutination-inhibiting antibody titers for both components were determined a few weeks after vaccination. They demonstrated that a good antibody response had been induced in a high percentage of volunteers. The hemagglutination inhibiting titers and percentage of seroconversion for both components were comparable to the results obtained after the intranasal administration of each component separately.