Defining the Burden of Disease of RSV in Europe: estimates of RSV-associated hospitalisations in children under 5 years of age. A systematic review and modelling study.

BackgroundRespiratory syncytial virus (RSV) infections cause an estimated 22-50 million episodes of acute lower respiratory infections (ALRI) every year in children younger than 5 years. To date, no overall estimate of RSV-associated hospitalisations in children under 5 years has been published for the European Union (EU). Through statistical modelling, we estimated the RSV hospitalisation burden in children under 5 years of age in EU countries and Norway, by age group and country. MethodsWe collated national RSV-associated hospitalisation estimates calculated using linear regression models in children under 5 years via the RESCEU project for Denmark, England, Finland, Norway, the Netherlands and Scotland during 2006-2018. A systematic literature review was conducted to collect additional estimates. Using the multiple imputation and nearest neighbour matching extrapolation methods, we estimated RSV-associated hospitalisation rates in all EU countries. ResultsAdditional estimates for Spain and France were found in the literature and added to the analysis. We estimated that an average of 245,244 (95%CI 224,688-265,799) hospital admissions with a respiratory infection per year were associated with RSV in children under the age of 5, with most cases occurring among children aged less than 1 year (75%). Infants aged less than 2 months represented the most affected group (71.6 per 1,000 children; 95%CI: 66.6-76.6). The hospitalisation rates varied widely across countries: for example, estimated rates in the 0-2 months age group ranged from 47.4 (37.5-57.3) per 1,000 in the Netherlands to 98.3 (88.5-108.1) per 1,000 in France. ConclusionTo our knowledge, this is the first attempt to estimate the overall RSV hospitalisation burden in children under the age of 5 years in the EU. Our findings will help support decisions regarding prevention efforts, and they will also represent an important benchmark to understand changes in the RSV burden following the introduction of RSV immunisation programs in Europe.