[A prospective serological epidemiological investigation of hepatitis B virus infection in a prison]

2,443 male prisoners were under investigation, most of them were youth, and followed up for 12-36 (mean 23.7 +/- 11.4) months. Sera HBV markers were detected every year. The positive rate of HBsAg was 25.1%, in which transient HBV carriers were 14.7% and chronic asymptomatic HBV carriers (AsC) were 85.3%. Seroconversion rate of HBsAg in AsC was 1.4% per year. The positive rate of anti-HBs was 46.3%, anti-HBs diminished in 6.0% per year. It was suggested that the antibody response to frequent exposure to HBV persisted for a long time. HBeAg seroconversion was 22.3% per year, and its reoccurrence was 7.9% per year, indicating the fluctuation and stability of infection status. The prevalence rate of HBV infection (with one or more than one of HBsAg, anti-HBs or anti-HBc) was 81.1%. Incidence of HBV infection among those susceptible persons found at first investigation was 22.3% per year.