Hepatitis B vaccine administered to children and adolescents at yearly intervals

Objective. Hepatitis B vaccines are usually administered on a schedule of 0, 1 to 2, and 6 months. Longer intervals between the second and third doses have been studied, but the effectiveness of hepatitis B vaccine administered at intervals of > 2 months between the first and second doses have not been studied. Our objective was to compare the antibody response in recipients of Engerix-B hepatitis B vaccine administered at 12-month intervals to the response to vaccine administered at 0-, 1-, and 6-month intervals. Methods. A total of 389 children, 5 through 16 years of age, were randomized to receive Engerix-B (10 mg) at a schedule of either 0-, 1-, and 6-month intervals or 0-, 12-, and 24-month intervals. Blood was drawn before and 1 month after the third dose. Results. Immediately before the third dose of vaccine, 92.3% of children who received vaccine on the 0-, 1-, and 6- month schedule and 88.8% of children who received the 0-, 12-, and 24-month schedule had antibody to hepatitis B surface (anti-HBs) antigen concentrations ≥ 10 mIU/mL. Of the children in the 0-, 1-, and 6-month schedule, 95% received the third dose according to protocol versus 90% of those in the 0-, 12-, 24-month schedule. The geometric mean anti-HBs concentration just before the third dose for recipients of the 0-, 1-, and 6- month schedule (117.9 mIU/mL) was somewhat lower than that for the children who had received vaccine on the 0-, 12, and 24-month schedule (162.1 mIU/mL). One month after the third dose, > 98% of all children had anti-HBs concentrations ≥ 10 mIU/mL and high geometric mean antibody concentrations were observed in both group: 5687 mIU/mL for children on the 0-, 1-, and 6- month schedule and 3159 mIU/mL for children on the 0-, 12-, and 24-month schedule. Body mass index was correlated inversely with final antibody concentration, but age was not a factor after adjustment for body mass index. Discussion. Engerix-B administered on a 0-, 12-, and 24-month schedule is highly immunogenic. Providers should consider this alternate immunization schedule for children who are at low risk of immediate exposure to hepatitis B infections.