Seroprevalence and Shifting Endemicities of Hepatitis A Virus Infection in Two Contrasting Geographical Areas in Indonesia

<i>Background and Objectives:</i> Hepatitis A is an infectious disease caused by the hepatitis A virus (HAV), which is transmitted via the fecal-oral route, either through the consumption of contaminated food and water or through direct contact with an infected individual. The incidence of HAV is closely associated with socioeconomic factors, access to clean drinking water, sanitation safety, and hygiene. This study aimed to determine HAV seroprevalence and shifting endemicities of hepatitis A virus infection. The seroprevalence and endemicity status were assessed based on the age at the midpoint of population immunity (AMPI). <i>Materials and Methods:</i> A cross-sectional seroprevalence study was conducted in two contrasting areas (urban vs. rural) in Bandung, Indonesia. All participants underwent serological testing for anti-HAV IgG using a chemiluminescent microparticle immunoassay (CMIA) and participated in questionnaire interviews. Socioeconomic status was assessed using the Water/sanitation, Assets, Maternal education, and Income (WAMI) index. All statistical analyses were performed using SPSS 18, with a <i>p</i>-value of <0.05 considered significant. <i>Results:</i> A total of 1280 participants were tested (640 living in urban areas; 640 living in rural areas). The total prevalence of HAV seropositivity was 50.5% (95% confidence interval [CI]: 47.7-53.3%), with prevalences of 46.1% (95% CI: 42.5-54.4%) across urban sites and 54.7% (95% CI: 50.7-58.6%) across rural sites. The AMPI was within the 20-24-year age group, with an age point of 22 years, classified as an intermediate HAV endemicity status. <i>Conclusions:</i> the study found a shift in HAV endemicity status from low to intermediate, supporting the need for large-scale national hepatitis A vaccination in Indonesia.