Background: Hepatitis B virus (HBV) infection is a significant public health problem in Vietnam, yet fewdata exist about the extent of infection. Purpose: To determine seroprevalence of HBV and the risk factors forHBV infection using a population-based epidemiological study in Vietnam. Methods: A 400 person survey forseroprevalence of hepatitis B surface antigen (HBsAg) and HBV infection was carried out in five hamlets in theLinhson village of Thainguyen province from June to August 2006. HBV infection was defined as the presenceof antibodies to hepatitis core antigen (HBcAb) and/or HBsAg, with or without HBsAg. Potential risk factorsfor HBV transmission were determined by a structured questionnaire. Results: Of the 383 respondents aged 18-70 years, 34 (8.8%) tested positive for HBsAg, of whom 21 (61.8%) were HBeAg-negative and hepatitis B eantibody (HBeAb) positive, and 22 (64.7%) had normal alanine aminotransferase (ALT) levels. The prevalenceof HBV infection was 51.8% and increased significantly with age. Only 5.2% showed evidence of vaccination.On multivariate analysis, five predictors were found for HBV infection: male gender (OR 1.6; 95% CI 1.3-1.7),age greater than 40 (OR 2.1; 95% CI 1.4-3.3), Kinh ethnicity (OR 1.8; 95% CI 1.1-2.7), a low level of education(OR 1.7; 95% CI 1.0-2.7), and a history of surgery (OR 1.9; 95% CI 1.0-3.5). Conclusions: The observed highprevalence of current and past infection with HBV in rural Vietnam highlights the need for close monitoring.
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