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

Background Respiratory 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.

Cyclic 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.

Among 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 €, similar to influenza.

This 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. Competing Interest Statement CN, EB, SF, EB are employees of Pfizer. VB, EL, CFB, ML are employees of HORIANA, which was contracted by Pfizer. LW and PV has received consulting fees from Pfizer for this work. PL has received consulting fees or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from GlaxoSmithKline, Moderna, and Pfizer. JSC has no conflict of interest to declare. Funding Statement This work was supported by Pfizer. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study uses aggregated data from the French public datasets PMSI, CepiDc and EMR. Four requests to the appropriate authorities were made to obtain access to these datasets (Sante Publique France, CepiDc, CNAM, and EMR). Under French legislation of the Commission nationale de l'informatique et des libertes (CNIL), the requirement for ethical approval for studies using aggregated data from public datasets is waived. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability The national datasets used in this study can be requested from the appropriate French authorities, the model datasets used for analysis are not publicly available.