HEPATITIS-A VACCINATION - SCHEDULE FOR ACCELERATED IMMUNIZATION

Hepatitis A vaccine, strain HM]75, was investigated for immunogenicity and tolerability in a prospective multicentre trial. The following vaccination schedules and antigen contents were evaluated days 0 and 14 with 720 ELISA units (El. U) of antigen, days 0 and 28 with 720 El. U and days 0 and 28 with 360 El. U. In all study groups, the seroconversion rates following two vaccinations were between 95 and 100%. Higher geometric mean concentrations of antibody to hepatitis A virus (anti-HAV) were reached by the vaccine containing 720 El. U of HAV antigen. The vaccine was equally well tolerated in all groups. In addition, an abbreviated schedule, in which 720 El. U of HAV antigen was given on days 0 and 14, resulted in 100% seroconversion by day 28 and a level of anti-HAV that was substantially higher than that observed after passive immunization. This implies that such a vaccine could replace immune globulin administration if time permits.