ABSTRACT
BACKGROUND: Korea is an endemic area of viral hepatitis B. In spite of the HBV vaccination program since 1983, the prevalence of HBV antigen had remained high, which was 3.9% in male, 2.7% in female in 1994. But there is no approved management guideline on isolated anti-HBc and the meaning of which is not clear except the evidence of past infection. Therefore, we tried to investigate the factors which influence the seroconversion of anti-HBs during follow-up period. METHODS: Medical records of 239 subject with isolated anti-HBc, who visited a health promotion center from 1995 to 1997 and who were retested at least once during the 1-3 years' follow-up period, were analyzed. RESULTS: The seroconversion rate of anti-HBs was 45.61%(109/239) on the follow-up test. The number of newly vaccinated or non-newly vaccinated subjects during the follow-up period was 156 and 72, respectively. The seroconversion rate of anti-HBs of each group were 57.69%(90/156) and 22.22% (16/72) respectively(p<0.01). The subjects without previous history of HBV vaccination was 103. Among them the seroconversion rate of anti-HBs of the newly vaccinated or the non newly vaccinated group were 59.70%(40/67) and 22.22% (8/36), respectively(p<0.01). Sex, age, BMI, smoking, previous history of HBV vaccination did not influence significantly on the seroconversion rate of anti-HBs among the subjects with isolated anti-HBc. CONCLUSIONS: The seroconversion rate in people with isolated anti-HBc was significantly higher in the newly vaccinated than the non-newly vaccinated regardless of the previous history of HBV vaccination in this study. In spite of the non-differentiation of an-amnestic response from primary antibody response, we can expect to benefit from HBV vaccination in those with isolated anti-HBc.59.70%(40/67) and 22.22% (8/36), respectively(p<0.01). Sex, age, BMI, smoking, previous history of HBV vaccination did not influence significantly on the seroconversion rate of anti-HBs among the subjects with isolated anti-HBc. CONCLUSIONS: The seroconversion rate in people with isolated anti-HBc was significantly higher in the newly vaccinated than the non-newly vaccinated regardless of the previous history of HBV vaccination in this study. In spite of the non-differentiation of an-amnestic response from primary antibody response, we can expect to benefit from HBV vaccination in those with isolated anti-HBc.