Year-round RSV Transmission in the Netherlands Following the COVID-19 Pandemic - A Prospective Nationwide Observational and Modeling Study.

We initiated a nationwide prospective study to monitor RSV-related pediatric hospitalizations in 46 hospitals throughout the Netherlands between May 2021 - August 2022. We showed year-round RSV transmission in the Netherlands after an initial 2021 summer outbreak. The pattern was unprecedented and distinct from neighboring countries. We extended a dynamic simulation model to evaluate the impact of waning immunity on pediatric RSV hospitalizations in the Netherlands using four different scenarios. Our results suggest that the observed continuous RSV transmission pattern could be associated with waning immunity due to the period of very low RSV circulation during the COVID-19 pandemic.