Hepatitis E in Kathmandu Valley: Insights from a Representative Longitudinal Serosurvey

Hepatitis-E virus (HEV), an etiologic agent of acute inflammatory liver disease, is a significant cause of morbidity and mortality in South Asia. HEV is considered endemic in Nepal; but data on population-level infection transmission is sparse. We conducted a representative longitudinal serologic study between February 2019 and April 2021 in urban and peri-urban areas of central Nepal to characterize community-level HEV transmission. Individuals were followed up to four times, during which capillary blood samples were collected on dried blood spots and tested for anti-HEV immunoglobulin-G antibodies. Analyzing 2513 dried blood samples from 923 participants aged 0-25 years, we found a seroprevalence of 4.8% and a seroincidence rate of 10.9 per 1000 person-years. Notably, young adults, including women of childbearing age, faced the highest incidence of infection. Geospatial analysis identified potential HEV clusters in Kavre and Kathmandu districts, emphasizing the need for targeted interventions. Water source played a crucial role in HEV transmission, with individuals consuming surface water facing the highest risk of seroconversion. Our findings underscore the endemic nature of HEV in Nepal, emphasizing the importance of safe water practices and potential vaccination strategies for high-risk groups.