IMMUNOGENICITY OF HEPATITIS-B VACCINES - IMPLICATIONS FOR PERSONS AT OCCUPATIONAL RISK OF HEPATITIS-B VIRUS-INFECTION

Objectives: To assess risk factors for decreased immunogenicity among adults vaccinated with hepatitis B vaccine and to determine the import ance of differences in immunogenicity between vaccines among health ca re workers (HCWs). Design: Randomized clinical trial and decision anal ysis. Participants: HCWs. Main Outcome Measures: Development of seropr otective levels of antibody to hepatitis B surface antigen (anti-HBs) and the number of expected chronic hepatitis B virus (HBV) infections associated with lack of protection. Results: Overall, 88% of HCWs deve loped seroprotection. Risk factors associated with failure to develop seroprotection included increasing age, obesity, smoking, and male gen der (P < .05). Presence of a chronic disease was associated with lack of seroprotection only among persons greater than or equal to 40 years of age (P <.05). The two vaccines studied differed in their overall s eroprotection rates (90% vs. 86%; P < .05), however, this difference w as restricted to persons greater than or equal to 40 years of age (87% vs. 81%; P < .01). Among HCWs greater than or equal to 40 years of ag e, the decision anal)sis found 44 (0.34/100,000 person-years) excess c hronic HBV infections over the working life of the cohort associated w ith use of the less immunogenic vaccine compared to the other. Conclus ion: Hepatitis B vaccines are highly immunogenic, but have decreased i mmunogenicity associated with increasing age, obesity, smoking, and ma le gender; and among older adults, the presence of a chronic disease. One of the two available vaccines is more immunogenic among older adul ts; however, this finding has little clinical or public health importa nce. Hepatitis B vaccines should be administered to persons at occupat ional risk for HBV infection early in their career, preferably while t hey are still in their training.