Intradermal inoculation with Heptavax-B. Immune response and histologic evaluation of injection sites

The high cost of hepatitis B vaccine has limited its widespread use. Low-dose, intradermal injections of vaccine represent one option for reducing the cost. In this study, 92 nonimmune medical students were given three 0.1-mL intradermal injections of Heptavax-B containing 2 micrograms of hepatitis B surface antigen (HBsAg) at 0, 1, and 6 months. By 6 months, 90% of the subjects had developed protective levels of antibody to HBsAg (greater than or equal to 10 mIU/mL). Follow-up at 1 year showed a geometric mean concentration of antibodies to HBsAg of 396 mIU/mL for the group, and 95% had levels of antibody to HBsAg greater than or equal to 10 mIU/mL. A level of antibody to HBsAg of greater than 100 mIU/mL also was observed in more than 75% of subjects. Side effects included induration of the inoculation site in 18% at 6 months, which disappeared by 12 months, and macules that persisted at 1 year in 63%. The administration of hepatitis B vaccine intradermally is an attractive, low-cost alternative in the United States, where universal vaccination of preschool children or adolescents is being contemplated, and where booster doses are being considered.