Kinetic Modelling of the Decay of Respiratory Syncytial Viruses (RSV) Facilitated a Robust Wastewater-Based Surveillance for RSV.

Wastewater-based epidemiology (WBE) is a promising tool for monitoring respiratory pathogens, yet the rapid in-sewer decay of viruses limits its application in low-incidence settings. This study investigates the decay rates of respiratory syncytial virus (RSV) in wastewater under various conditions to enhance the utility of WBE for forecasting RSV outbreaks. Laboratory-scale recirculating sewer systems were employed to simulate in-sewer decay of RSV at different temperatures, organic concentrations, and total suspended solids (TSS) levels. A first-order decay model revealed a significant temperature dependence, with the decay rate increasing approximately 30-fold from 4 to 35 °C. Conversely, higher TSS concentrations provided substantial protection to RSV particles, extending the T90 by up to sevenfold, whereas SCOD exhibited minimal impact. Based on these findings, a multiple linear regression model was established to identify key predictors. This study underscores the importance of understanding RSV decay kinetics for accurate WBE and highlights the value of kinetic modelling in correcting in-sewer viral loss for optimized wastewater surveillance.