Enterovirus 71 seropositivity among children and adolescents in Bangladesh.

Objectives: The world has witnessed an increase in non-polio enterovirus infections. This study assessed the seroprevalence of enterovirus 71 (EV71) neutralizing antibodies (NAbs) and explored associated risk factors among children and adolescents in Bangladesh. Methods: Between March 2019 and March 2020, a cross-sectional survey was conducted in one urban and one rural district of Bangladesh. A total of 1207 children aged 0-17 years were enrolled, including 607 from urban and 600 from rural areas. Serum samples were tested using a cytopathic effect-based microneutralization assay to measure EV71 NAb titers. Demographic and socio-epidemiological data were also collected through structured interviews. Results: Overall, 817 (67.7%) were seropositive for EV71, with 68.3% in urban and 31.7% in rural areas. Age-specific seroprevalence in urban vs rural settings was: <6 months, 96.0% vs 38.9%; 6-71 months, 90.3% vs 35.1%; 6-11 years, 92.7% vs 80.4%; 12-17 years, 100% vs 77.6%. In urban areas, having an indoor toilet was linked to lower seropositivity (P = 0.03). In rural areas, older age, lower parental education, and parental unemployment were significant factors. Conclusions: The high EV71 seroprevalence in Bangladeshi children indicates widespread exposure. Further research on non-polio enterovirus, including EV71, is needed to inform surveillance, prevention, and potential vaccine strategies.