Background: A considerable number of people remain unprotected against hepatitis B. These people may require immunization at short notice before being exposed to situations or locations where a risk of infection is present. Currently, full active immunization against hepatitis B, when administered according to recommended schedules, takes 2–6 months. This open, randomized multicentric study evaluated the reactogenicity and immunogenicity of a recombinant hepatitis B vaccine in adults when it was administered according to three different rapid vaccination schedules.

Methods: Five hundred and twenty four healthy adults (aged 18–59 years) were randomly divided into three groups. Hepatitis B vaccine was given intramuscularly in the deltoid muscle at months 0, 1, and 2 (group A); weeks 0, 14, and 28 (group B); and weeks 0, 7, and 21 (group C). Symptoms were recorded by the subjects on individual diary cards. AntiHBs were measured using radioimmunoassay (AUSAB-Abbott); a seroprotective titer was defined as 10 IU/L.

Results: At day 28, no significant difference in seroprotection rates (SPRs) i.e., seroconversion ≥ 10 IU/L, was observed, between groups B (55.6%) and C (65.2%), but both these groups had significantly greater SPRs than group A (15.0%). Although not significant (p= .07), groups B and C also had higher SPRs than group A (78.5% and 76.4% versus 65%) at day 56. One month after completing the three dose schedules, the SPRs were as follows: 89.0% (group A); 78.5% (group B); and 76.4% (group C), increasing to > 94% at month 7 to 8 in all three groups. The SPRs at month 13 were 95.8%, 98.9%, and 98.6%, respectively. Among the three groups, no significant differences were observed from month 2 onwards in either SPRs or geometric mean titers. In groups A, B, and C, 3.7%, 5.0%, and 7.1% of the vaccine injections were associated with local symptoms. Also 8.3%, 6.2%, and 6.3% of subjects exhibited general symptoms following each vaccine dose; all symptoms were transient and resolved spontaneously.

Conclusions: This recombinant hepatitis B vaccine administered at weeks 0, 7, 21, or at weeks 0, 14, 28, rapidly elicits high rates of seroprotection, which persist at least until month 12.