Recombinant Yeast Vaccine is a non-infectious viral vaccine produced from Hepatitis B surface antigens (HBsAg) expressed by recombinant yeast. The fragment of Hepatitis B virus gene, that is encoding HBsAg, is cloned into Saccharomyces cerevisae, and the vaccine is derived from the culture of recombinant yeast strains. After purification, inactivation and adsorption, the antigen is formulated into the vaccine. It doesn’t contain thimerosal.