Protection Afforded By Avian Influenza Vaccination Programs Consisting Of A Novel RNA Particle And An Inactivated Avian Influenza Vaccine Against A Highly Pathogenic Avian Influenza Virus Challenge In Layer Chickens Up To 18 Weeks Post Vaccination.

AbstractThe efficacies of an oil adjuvanted-inactivated reverse genetics derived H5 avian influenza virus (AIV) vaccine and an alphavirus replicon RNA particle (RP) AIV vaccine were evaluated in commercial leghorn chickens. Challenge utilized A/Turkey/MN/12582/2015, an isolate representing the U.S. H5N2 Clade 2.3.4.4 responsible for the 2015 highly pathogenic avian influenza (HPAI) epornitic in commercial poultry the United States. As part of long term, 36-week study, chickens were challenged at seven weeks of age after receiving a single vaccination, at 18 weeks of age after following a vaccine prime-single boost and at 36 weeks of age after a prime- double-boost. All vaccine programs reduced virus oropharyngeal and cloacal shedding and mortality compared to the non-vaccinated control birds however, chickens receiving at least one administration of the RP vaccine generally had diminished viral shed especially from the cloacal swabbings. A detectable serum antibody response and protection was observed thr...