[Experimental study of residual virulence of viral vaccine strains]

Residual virulence of three vaccinia strains: Neurovaccine, L-IVP, and its recombinant Revacs-B expressing HBs and preS2 antigens of hepatitis B virus is compared. Insertion of HBs and preS2 antigens of hepatitis B virus in the genome of vaccinia virus strain L-IVP decreases its residual virulence and leads to a benign course of vaccinal reaction involving no deaths of rabbits, cotton rats, or guinea pigs. We may expect that recombinant vaccine Revacs B based on L-IVP strain will cause no postvaccinal complications under conditions of an appreciable decrease in population immunity to vaccinia virus.