Hepatitis B virus vaccination for older adults

OBJECTIVE: To compare in adults more than 50 years old the tolerability and immunogenicity of vaccination with recombinant hepatitis B surface antigen (HBs) compared with vaccination with recombinant hepatitis B protein PreS2+S, and to investigate the safety and immunogenicity of a fourth vaccine dose in poor and non-responders. DESIGN: Randomized, double-blind prospective study. SETTING: General clinical research center for outpatient evaluation and vaccination. SUBJECTS: Adults older than age 50 who were in general good health and with no known risk factors for acquiring or serologic evidence of hepatitis B virus infection. INTERVENTION: Subjects were randomized to receive 10 meg HBs (Recombivax(R), Merck, Sharp and Dohme), 12 meg PreS2+S, or 24 meg PreS2+S vaccine at 0, 1, and 6 months. Poor and non-responders (anti-Hbs < 10 mIU/mL at month 9 and/or 12) were encouraged to receive a fourth vaccine injection. MEASUREMENTS: Diary records of temperature and local and systemic reactions following each vaccination were maintained by all subjects. Anti-HBs levels were measured by radioimmunoassay before the first injection, at 1, 2, 3, 6, 7, 9, and 12 months after for all subjects, and 1 month after the fourth injection for the group of poor and non-responders. MAIN RESULTS: Twenty men and nine women (mean age +/- SD, 66 +/- 8.0 years) were enrolled. Ten subjects received HBs vaccine, nine received 12 meg PreS2+S vaccine, and 10 received 24 meg PreS2+S vaccine. One subject in the HBs group dropped out, and data were analyzed for the remaining 28 subjects. There were no differences in rates of side effects reported by each of the three groups. Overall, minor local adverse reactions occurred in 12 (40%) after at least one of the first three vaccinations. Systemic side effects occurred in five (17%) after the first vaccination, in one after the second, but in none after the third. The 24-mcg PreS2+S vaccine was not more immunogenic than the HBs vaccine, and the 12-mcg PreS2+S vaccine was judged inadequate. Nineteen of 22 (86%) poor and non-responders received a fourth vaccination. Minor local adverse reactions were reported by six (32%), and none reported a systemic side effect. For the 12 subjects receiving a fourth injection of HBs or 24 meg PreS2+S vaccine, the proportion of responders 1 month following the fourth injection was greater than for 1 month following the third injection (11 of 12 [92%] versus 12 of 19 [63%], respectively, P<.05). CONCLUSION: For adults more than 50 years of age who have low anti-HBs levels after three vaccine injections, a fourth injection is well tolerated and results in improved immunogenic response.