Estimation of GP visits, hospitalizations and deaths attributable to RSV and influenza and costs associated with hospitalizations in older adults in France, 2010-2020

BackgroundRespiratory syncytial virus (RSV) is a leading cause of respiratory infection, causing substantial numbers of hospitalizations and deaths, particularly among vulnerable groups such as infants and older adults. However, its true burden in the adult population is often underestimated due to diagnostic challenges and infrequent standard-of-care testing. This study aimed to estimate the incidence of general practitioner (GP) visits, hospitalizations, and deaths attributable to RSV in French adults aged [≥]65 years using a time-series model-based approach. In addition, costs associated with hospitalizations were calculated. MethodsCyclic Poisson regression models and weekly data from French medical administrative databases and electronic medical records over ten epidemic seasons (2010-2020) were used to estimate incidences for RSV and influenza. The results were stratified by age group, diagnosis causes (respiratory and cardiorespiratory) and diagnosis type (primary and secondary). Average costs per hospitalization were calculated and multiplied by the number of hospitalizations estimated. ResultsAmong adults aged [≥]65 years, we estimated RSV infection was responsible for 647,619 GP visits 24,319 hospitalizations, and 878 deaths per year. Incidence rates for GP visits for RSV were twice as large as for influenza; hospitalization rates were similar and mortality was lower. The mean annual cost of RSV-attributable hospitalizations was 105 million {euro}, similar to influenza. ConclusionsThis study highlighted the burden of RSV disease in the adult population in France is higher than previous reported. We envisage that this model-based approach will be instrumental in evaluating the impact of RSV vaccination campaigns. Key points- The estimated incidence of RSV infection in older adult is higher than previously reported. - RSV is responsible for more GP visits, similar hospitalisations but fewer deaths compared to influenza. - Model-based studies are essential to study RSV epidemiology.