Vaccines developed for H5 highly pathogenic avian influenza in China.

Since the first detection of highly pathogenic H5N1 avian influenza virus from sick goose in Guangdong province in China in 1996, scientists in China started to develop vaccines for avian influenza pandemic preparedness. An H5N2 inactivated vaccine was produced from a low pathogenic virus, A/turkey/England/N-28/73, and was used for the buffer zone vaccination in the H5N1 outbreaks in 2004 in China. We also generated a low pathogenic H5N1 reassortant virus A/Harbin/Re-1/2003 (Re-1) that derives its HA and NA genes from GSGD/96 virus and six internal genes from the high-growth A/Puerto Rico/8/34 (PR8) virus by using plasmid-based reverse genetics. The inactivated vaccine derived from Re-1 strain could induce more than 10 months protective immune response in chickens after one dose inoculation, and most importantly, this vaccine is immunogenic for geese and ducks. An H5N1 fowlpox vectored live vaccine was also generated by inserting the HA and NA genes of GSGD/96 virus in the genome of a fowlpox vaccine strain. Laboratory tests indicated that after one dose of immunization of this vaccine, chickens could develop an over than 40 weeks protective immune response against H5N1 virus challenge.