Simultaneous passive and active immunization against hepatitis B: noninterference of hepatitis B immune globulin with the anti-HBs response to reduced doses of heat-inactivated hepatitis B vaccine.

The effect of simultaneous administration of hepatitis B immune globulin on the antibody response to a low dose of heat-inactivated hepatitis B vaccine was investigated in 175 health care workers. Subjects were divided into four groups: Groups I and II received 3 monthly injections of a reduced dose (0.6 microgram) of a heat-inactivated hepatitis B vaccine (the usual dose being 3 micrograms) along with 500 IU of hepatitis B immune globulin simultaneously with the first injection of vaccine; Groups III and IV received the vaccine only. In addition, Groups I and III received a final booster injection with 0.6 microgram of the vaccine 8 months after the initial injection. Anti-HBs passively acquired from hepatitis B immune globulin did not interfere with the development of an active antibody response to the vaccine: the anti-HBs conversion rates were similar in persons treated with the combined regimen (89%) as in those who received the vaccine only (91%). At 3 and 5 months after the first injection, however, anti-HBs titers in the recipients of vaccine alone were slightly but statistically significantly higher than those of persons who received both hepatitis B immune globulin and vaccine; but at 8 months, this difference was no longer statistically significant. After a booster inoculation at 8 months, the geometric mean titer of anti-HBs increased 7- to 8-fold in antibody-positive vaccinees, regardless of whether hepatitis B immune globulin had been given earlier. Moreover, 6 of 13 nonresponders to the initial three vaccine injections developed anti-HBs after the booster inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)