[Immunogenicity and tolerance of a combined hepatitis A/B vaccine. Preliminary results with a candidate vaccine].

AIM OF STUDY: Active immunization against hepatitis A having been undertaken in Germany since January 1993, a multicentre study was conducted to test, for the first time, immunogenicity of and tolerance to a candidate vaccine against hepatitis A and B. SUBJECTS AND METHODS: 50 healthy volunteers aged 18-40 years, negative for antibodies against hepatitis A (HAV) and B (HBs), received three intramuscular injections of the candidate vaccine (720 EIU of strain HM 175 and 20 micrograms recombinant HBsAg) in a total volume of 1 ml, on day 1 and then, one month and 6 months later. RESULTS: Four weeks after the first injection the seroprotection rate (percentage of subjects with protective antibody titres) was 90% for HAV and 28% for HBs. The second injection produced seroconversion rates of 98% and 50%, respectively, and after the third one of 100% and 98%. All reported side effects were minor, of short duration and decreased after each injection. After the first injection, effects at the site of injection occurred in 50% of subjects, decreasing to 6% after the third one. The only systemic side effect, headache, occurred in only 4% of subjects and only after the first injection. CONCLUSION: The test vaccine against hepatitis A and B proved to be highly immunogenic, safe and well tolerated.