Protective efficacy of the bivalent inactivated vaccine against lethal HPAI H5N1 virus infection.

ASPF chickens were challenged intranasally with 100 µl of 105.0 EID50 of homologous H5N1 virus 3 weeks post-vaccination. BHemagglutination-inhibition titers against the homologous antigen were determined 3 weeks after vaccination using chicken erythrocytes. CDepression was observed in non-vaccinated chickens before death. DVirus replication was determined at day 5 post-infection. Log EID50 equivalents were determined by quantitative real-time reverse transcriptase polymerase chain reaction. MDT, mean death time in days. N/A, not applicable.