1. Protection of layers and breeders against homologous or heterologous HPAIv by vaccines from Korean national antigen bank.
- Author
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Kang YM, Cho HK, Kim HM, Lee CH, Kim DY, Choi SH, Lee MH, and Kang HM
- Subjects
- Animals, Antibodies, Viral immunology, Chickens immunology, Hemagglutinin Glycoproteins, Influenza Virus genetics, Influenza A Virus, H5N1 Subtype immunology, Influenza Vaccines genetics, Influenza in Birds virology, Poultry immunology, Republic of Korea epidemiology, Vaccination methods, Vaccines, Inactivated pharmacology, Influenza A virus immunology, Influenza Vaccines immunology, Vaccines, Inactivated immunology
- Abstract
Korean government has selected and stocked five type antigens of two clades as Korean national antigen bank having high possibility of introduction to Korea. We aimed to evaluate the efficacy of the clade 2.3.2.1c and 2.3.4.4c H5Nx vaccines from the Korean avian influenza (AI) national antigen bank for emergency preparedness for their potency and protective efficacy against lethal homologous and heterologous viruses in layer and breeder chickens practically. The PD
50 (dose of vaccine that protects 50% of chickens from viral challenge) of all vaccinated groups was >50, which was satisfied with minimum antigen requirement of OIE, and the PD50 levels of the two vaccines differed depending on strain and chicken breed. In homologous challenge, all vaccinated groups exhibited 100% survival with no clinical symptoms and high levels of pre-challenge protective immunity (7.2-8.5 log2 ), although they did not completely prevent virus shedding. On the other hand, against heterologous virus challenge, vaccinated animals exhibited 62.5-80% survival with lower antibody titers (2.3-3.4 log2 ) and a longer period of virus shedding (14 days post infection [dpi]). Our results suggest that the clade 2.3.2.1c and 2.3.4.4c H5Nx vaccines are good candidates for emergency vaccination of commercial chickens and support the idea that close genetic matching between vaccine and challenge virus provides the best protection.- Published
- 2020
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