Passive and active immunization against hepatitis B virus infection: optimal scheduling in healthy young adults.

Recent in vitro data suggest that an enhanced humoral response to hepatitis B surface antigen (HBsAg) may be achieved when HBsAg is administered to monocyte/lymphocyte mixtures in the presence of antibody to HBsAg (Anti-HBs). In order to determine whether the same response can be achieved in vivo and whether this phenomenon can be used to augment an individual's response to hepatitis B virus (HBV) vaccination, serum antibody levels to hepatitis B surface antigen (anti-HBs) were determined in five groups of healthy young volunteers receiving passive hepatitis B immunoglobulin (HBIG) at various time intervals around a fixed HBV vaccination schedule. Thus HBIG (0.06 ml/kg) was administered to individuals in group I at -4 weeks; group II: -2 weeks; group III: simultaneously with vaccination; group IV; +2 weeks; and group V: +4 weeks following the onset of active immunization. A sixth group of volunteers received HBIG alone. The results of the study indicated that following the initial vaccination, individuals receiving HBIG prior to vaccination responded more often and with slightly higher anti-HBs levels than those receiving HBIG simultaneously or following the onset of vaccination. These differences, however, became less prominent and ultimately non-existent with subsequent boosts of the vaccine. The study also demonstrated that males and individuals over thirty do not respond to HBV vaccination as well as females or those under thirty.