ST. PETERSBURG, Jan. 21 (Xinhua) -- Russian scientists have developed a new vaccine strain against the highly pathogenic H5N1 avian influenza virus, the Russian Science Foundation announced on Tuesday.
The new strain precisely matches currently circulating variants and targets contemporary H5N1 viruses while remaining safe for both animals and humans, the foundation said on its website, adding that the research was carried out by scientists from the St. Petersburg State University of Veterinary Medicine and the A.A. Smorodintsev Research Institute of Influenza.
Highly pathogenic H5N1 continues to circulate worldwide, causing mass mortality among domestic and wild birds and significant economic losses. Its high variability and ability to cross species barriers reduce the effectiveness of older vaccines that do not match circulating strains, it said.
The scientists used reverse genetics to engineer the virus. Genes encoding hemagglutinin and neuraminidase from an H5N1 virus isolated from a black-headed gull in 2023 were modified to reduce pathogenicity and combined with genes from a safe laboratory H1N1 strain, producing a hybrid virus that replicates efficiently in chicken embryos.
In vaccination experiments, chicks receiving two doses 14 days apart developed antibody levels against H5N1 ten times higher than the minimum required for protection, demonstrating the high immunogenicity of the new vaccine strain, according to the Russian Science Foundation. ■
