Nebulized Live-Attenuated Influenza Vaccine Provides Protection in Ferrets at a Reduced Dose

Abstract Live-attenuated influenza vaccine (LAIV) is delivered to vaccine recipients using a nasal spray syringe. LAIV delivered by this method is immunogenic at current doses; however, improvements in nasal delivery might allow for significant dose reduction. We investigated LAIV vaccination in ferrets using a high efficiency nebulizer designed for nasal delivery. LAIV nasal aerosol elicited high levels of serum neutralizing antibodies and protected ferrets from homologous virus challenge at conventional (10 7  TCID 50 ) and significantly reduced (10 3  TCID 50 ) doses. Aerosol LAIV also provided a significant level of subtype-specific cross-protection. These results demonstrate the dose-sparing potential of nebulizer-based nasal aerosol LAIV delivery.