Incidence and epidemiology of Respiratory Syncytial Virus infections in children in rural Bangladesh: a prospective observational study

BackgroundRespiratory syncytial virus (RSV) is a leading cause of acute respiratory infection (ARI) in young children worldwide, yet data from low- and middle-income countries (LMICs) are scarce. The data that are available are mostly hospital-based and urban. We conducted a prospective, community-based study to estimate the burden of RSV-associated ARI (RSV-ARI) among children <24 months in a rural area of Bangladesh. MethodsThe study was carried out in two villages within the Mirzapur Health and Demographic Surveillance System (HDSS) from August 2021 to June 2023. Village healthcare workers (VHWs) made weekly home visits to all registered households to identify ARI episodes in enrolled children <2 years, using the WHO ARI case definition. When ARI symptoms were reported, a nurse obtained written parental informed consent and collected a nasopharyngeal swab, which was tested for RSV by real-time RT-qPCR. We computed incidence per 1,000 child-years using Poisson regression, and estimated incidence rate ratios (IRRs) for male versus female and preterm versus term birth. Results3,667 children contributed 3,008 child years of follow-up, 5,907 ARI episodes were recorded and 4,586 specimens collected and tested; a total of 7.1% (324/4,586) were RSV-positive. The overall RSV-ARI incidence was 107.7 per 1,000 child years (95% CI 96.6-120.1). In the first six months of life, the incidence was 164.5 per 1,000 child years, 1.5 times higher than the two-year average. Preterm infants had a 50% increased RSV-ARI risk (IRR 1.5; 95% CI 1.2-2.0). Cough was present in 95% of RSV cases, and chest indrawing, a sign not included in the WHO ARI definition, occurred in 9.8%. ConclusionRSV-ARI imposes a substantial community burden among rural Bangladeshi children under two years, especially in early infancy. These findings support the introduction of RSV-specific interventions (maternal and infant immunization or monoclonal antibodies) in similar rural LMIC settings.