Immunogenicity of recombinant hepatitis B vaccine in urban black children from Ga-Rankuwa, Bophuthatswana, South Africa

Abstract

Many areas in Southern Africa have a relatively high endemicity for hepatitis B for which the only effective medical measure is vaccination. The aim of this study was to evaluate the antibody response to a recombinant hepatitis B vaccine (Engerix B; Smith Kline-Beecham) in a black urban population, with the use of the recommended regimen and a low dose, short course. One hundred eleven children seronegative for hepatitis B virus (5 to 19 years old) were randomized to receive one of the two vaccination schedules (20 micrograms at zero, 1 and 6 months or 2 micrograms at zero, 1 and 2 months). Antibody to hepatitis B surface antigen was determined 6 to 8 weeks after the last dose by radioimmunoassay (Ausab; Abbott Laboratories). The recommended schedule gave a seroconversion rate of 100% with a geometric mean titer of 585.9 mIU/ml. The low dose, short course schedule produced a seroconversion rate of 63.8% and a geometric mean titer of 73.8 mIU/ml. In the 5- to 9-year-old individuals, however, 71.6% seroconverted (geometric mean titer 114.2 mIU/ml). For cost reasons further investigations on low dose regimens are indicated.