Trends in the seroprevalence of hepatitis B surface antigen in the South Korean population

BACKGROUND: Trends in hepatitis B virus (HBV) infection are important in evaluating the effectiveness of the recommended routine vaccination of infants and adolescents. METHODS: The prevalence of HBV infection was determined in a representative sample of the Korea National Health and Nutrition Examination Survey for 1998 (n=9771) and 2009 (n=8304). Participants aged ≥10 years were tested for the hepatitis B surface antigen (HBsAg). RESULTS: The overall age-adjusted HBsAg seroprevalence was 4.6% (95% confidence interval (CI) 4.2-5.0%) in 1998 and 3.2% (95% CI 2.9-3.6%) in 2009, which represents a relative decrease of 30.4% between the two survey populations (p<0.05). The prevalence of HBsAg decreased among persons 10-19 years of age (from 2.2% to 0.3%), 20-29 years of age (from 5.4% to 2.5%), 30-39 years of age (from 6.1% to 4.3%), 40-49 years of age (from 5.1% to 4.7%), and 50-59 years of age (from 5.3% to 3.7%). HBsAg seroprevalence did not decrease among persons ≥60 years of age (2.7% vs. 2.9%). CONCLUSIONS: These data show a decline in HBsAg seroprevalence, primarily due to the dramatic decrease in adolescents and younger adults.