EFFECT OF AGE ON THE IMMUNOGENICITY OF YEAST RECOMBINANT HEPATITIS-B VACCINES CONTAINING SURFACE-ANTIGEN (S) OR PRES2+S ANTIGENS

A single-blind, multicenter, phase II trial of yeast recombinant hepatitis B virus (HBV) vaccines containing surface antigen (S) alone or with PreS2 (PreS2+S) was conducted in 282 healthy HBV-seronegative adults aged 20-59 years. Each volunteer was randomly assigned to receive HBV vaccine containing 10 mu g of S or one of three doses of PreS2 plus S: 2 + 10 mu g, 4 + 20 mu g, or 8 + 40 mu g. The level of antibody to HBV surface antigen reached depended on the dose of S, not PreS2, received. In each vaccine group, volunteers 20-39 years old had higher titers of anti-PreS2 and antibody to S than those 40-59 years old. The age-related effect on immune response to HBV vaccination suggests that adults should be immunized against hepatitis B at as early an age as possible and that older persons may need a higher dose or booster immunizations to achieve durable immunity.