Immunogenicity of a recombinant hepatitis B vaccine in hemophiliacs

Yeast-recombinant vaccines against hepatitis B virus (HBV) are now available, but there is no information about whether or not they are immunogenic in patients with hemophilia and other congenital bleeding disorders. Twenty micrograms of a recombinant vaccine expressing the adw serotype of the hepatitis B surface antigen (HBsAg) were given to 41 patients negative for HBV markers and again after 1 and 6 months. Ten percent of the vaccinees had anti-hepatitis B surface antibody (anti-HBs) responses, with titers of 10 mIU/ml or more, 1 month after the first dose of vaccine. The percentage of anti-HBs-positive patients increased to 54% after the second dose and to 98% after the third dose, with only one non-responder. Hence, the recombinant vaccine was immunogenic, with percentages of seroconversion and anti-HBs titers similar to those achieved with plasma-derived vaccines.