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Protection of White Leghorn chickens by U.S. emergency H5 vaccination against clade 188.8.131.52 H5N2 high pathogenicity avian influenza virus
- Kateri Bertran, Charles Balzli, Dong-Hun Lee, David L. Suarez, Darrell R. Kapczynski, David E. Swayne
- Vaccine 2017 v.35 no.46 pp. 6336-6344
- Influenza A virus, RNA, White Leghorn, adults, avian influenza, genes, hemagglutinins, immunity, laying hens, mortality, pathogenicity, poultry industry, vaccination, vaccines, viral shedding, viruses, China, United States
- During December 2014–June 2015, the U.S. experienced a high pathogenicity avian influenza (HPAI) outbreak caused by clade 184.108.40.206 H5Nx Goose/Guangdong lineage viruses with devastating consequences for the poultry industry. Three vaccines, developed based on updating existing registered vaccines or currently licensed technologies, were evaluated for possible use: an inactivated reverse genetics H5N1 vaccine (rgH5N1) and an RNA particle vaccine (RP-H5), both containing the hemagglutinin gene of clade 220.127.116.11 strain, and a recombinant herpesvirus turkey vectored vaccine (rHVT-H5) containing the hemagglutinin gene of clade 2.2 strain. The efficacy of the three vaccines, alone or in combination, was assessed in White Leghorn chickens against clade 18.104.22.168 H5N2 HPAI virus challenge. In Study 1, single (rHVT-H5) and prime-boost (rHVT-H5+rgH5N1 or rHVT-H5+RP-H5) vaccination strategies protected chickens with high levels of protective immunity and significantly reduced virus shedding. In Study 2, single vaccination with either rgH5N1 or RP-H5 vaccines provided clinical protection in adult chickens and significantly reduced virus shedding. In Study 3, double rgH5N1 vaccination protected adult chickens from clinical signs and mortality when challenged 20weeks post-boost, with high levels of long-lasting protective immunity and significantly reduced virus shedding. These studies support the use of genetically related vaccines, possibly in combination with a broad protective priming vaccine, for emergency vaccination programs against clade 22.214.171.124 H5Nx HPAI virus in young and adult layer chickens.