Sewage surveillance revealed the seasonality and prevalence of respiratory syncytial virus and its implications for seasonal immunization strategy in low and middle-income regions of China.

Respiratory syncytial virus (RSV) represents a significant global health threat, with a disproportionately high disease burden in low and middle-income regions (LMIRs). Estimating the prevalence of RSV infection at the community levels remains a huge challenge, particularly in LMIRs where clinical data are scarce. In this study, we first detected RSV RNA in the fecal samples from 300 patients to understand the fecal shedding patterns of RSV. Meanwhile, we conducted sewage surveillance of RSV in four geographically distinct LMIRs in China from April 2023 to June 2024. Real-time reverse transcription quantitative Polymerase Chain Reaction (RT-qPCR) was employed to monitor the dynamics of sewage RSV concentration in a typical sewershed from Yingkou, Xi'an, Nanchang, and Nanning, respectively. Subsequent amplicon sequencing was conducted to understand the genotype and mutations of sewage RSV. Through RT-qPCR, we observed two RSV epidemics that lasted from late April to May and October to February in both Yingkou and Xi'an. For Nanchang, only one RSV epidemic was observed which emerged from September to February. Notably, in Nanning, a prolonged RSV epidemic was observed from August to April, suggesting RSV vaccination in Nanning faced more challenges. Amplicon sequencing revealed that sewage RSV found in four LMIRs is genetically distinct, highlighting the need for local initiatives for wastewater monitoring of RSV. This study filled the gaps in previous assessment of suitability of RSV vaccination in LMIRs based on clinical surveillance, demonstrating the effectiveness of wastewater surveillance in guiding public health interventions.