Interference of antibody production to hepatitis B surface antigen in a combination hepatitis A/hepatitis B vaccine

A randomized trial comparing 3 manufacturing consistency lots of a combinat ion hepatitis A/hepatitis B vaccine to each other and to hepatitis A vaccin e and hepatitis B vaccine given separately and concurrently was done to eva luate safety, tolerability, and immunogenicity. Healthy volunteers greater than or equal to 11 years of age were divided into 4 groups. Each of 3 grou ps received a separate consistency lot of the combination vaccine, and 1 gr oup received separate but concurrent injections of hepatitis A and hepatiti s B vaccines. Injections were given at weeks 0 and 24. The combination vacc ine was generally well tolerated. The hepatitis A portion of the combinatio n vaccine produced clinically acceptable high seropositivity rates 4 and 52 weeks after the first injection. The hepatitis B portion of the vaccine di d not produce clinically acceptable seropositivity rates 4 weeks after the second injection. Lack of antibody production may be attributed, at least i n part, to immunologic interference.