Seroprevalence of hepatitis A virus infection in urban and rural areas in Vietnam

BACKGROUND/OBJECTIVES: The prevalence of hepatitis A virus (HAV) is associated with socioeconomic conditions, access to clean drinking water, and improvements in sanitation. In Vietnam, epidemiological data on HAV have been limited over the past two decades. This study aims to assess age-specific HAV seroprevalence across two distinct geographic regions, urban and rural areas, and identify the risk factors associated with HAV seropositivity in Vietnam. METHODS: This cross-sectional seroprevalence study was conducted in two distinct areas in Vietnam. Serological testing for anti-HAV total antibodies was performed, and socio-demographic questionnaires were administered to all participants. The age at the midpoint of population immunity (AMPI) was calculated and analyzed. RESULTS: A total of 1,281 participants aged 1-80 years were included, with 649 from urban areas and 632 from rural areas. Of the total participants, 33.2% were aged <15 years. Overall, HAV seropositivity was 69.2%, with urban areas exhibiting significantly lower seropositivity (57.9%) compared to rural areas (80.7%) (p < 0.001). The AMPI was 29 years, indicating Vietnam is at intermediate HAV endemicity. Multivariate analysis identified key risk factors for HAV infection, including age and rural residence. Conversely, participants with higher educational levels and those who consumed boiled drinking water were less likely to be HAV seropositive. CONCLUSIONS: The study identified significant differences in the HAV seroprevalence between urban and rural areas, providing critical data for public health officials. These findings highlight the key role of targeted public health interventions and vaccination programs in mitigating HAV infection rates and reducing the disease burden, particularly among high-risk populations in Vietnam.