Efficacy of avian influenza neuraminidase-specific vaccines in chickens.

This paper investigates the protection induced in chickens by live neuraminidase (N)-specific vaccines against highly pathogenic avian influenza. Vaccination with viruses belonging to N1 and N8 subtypes protected against challenge with virulent viruses of the same N subtype and irrelevant haemagglutinin (H) subtypes. The main advantage of N-specific vaccines is that they do not confuse serological diagnosis by haemagglutination inhibition tests. The anomalous cross-protection between influenza viruses of H1 and H5 subtypes could be exploited to control outbreaks caused by highly pathogenic H5 viruses by using vaccines based on H1 and the appropriate N.