Abstract
BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of acute respiratory infection (ARI) in young children, but evidence on burden from low- and middle-income countries has largely been derived from hospital-based studies. This prospective, community-based study estimated the burden of RSV-associated ARI among children younger than two years of age in rural Bangladesh. METHODS: This observational study was conducted in two unions of the Mirzapur sub-district, Tangail District, Bangladesh between August 2021 and June 2023. Village healthcare workers visited each household in the selected area weekly to identify ARI episodes among children younger than two years using the WHO definition. Following parental written consent, nurses collected nasopharyngeal swabs for RSV testing by RT-qPCR from children who were experiencing ARI episodes. RSV incidence and incidence rate ratios were estimated using Poisson regression. FINDINGS: Overall, 3667 children contributed to 3008 child-years of follow-up. Out of 5907 ARI episodes recorded, 4586 specimens were collected and tested. 7.1% of the samples (324/4586) tested positive for RSV. RSV infections showed a peak in August-September 2021 and October 2022-February 2023 with 37.6% and 16.1% of samples testing positive, respectively, and near-zero detection during the remaining months. The overall RSV-ARI incidence was 107.7 per 1000 child-years (95% CI: 96.6-120.1). The incidence was highest during the first six months of life (164.5 per 1000 child-years), which was 2.2 times higher (incidence rate ratio [IRR] 2.2; 95% CI: 1.6-3.0) than in the second year of life. Preterm infants had a 50% higher risk of RSV-ARI (IRR 1.5; 95% CI: 1.2-2.0) than term infants. Cough was present in 95.7% and chest indrawing was observed in 9.8% of RSV infections. INTERPRETATION: RSV-ARI imposes a substantial community burden among rural Bangladeshi children, especially in infancy. These findings support consideration of RSV-specific interventions, such as maternal immunisation or monoclonal antibodies for infants to address the disease burden. FUNDING: The Robert Koch Institute, Germany; and the International Vaccine Institute (IVI), South Korea.