Respiratory Syncytial Virus–Associated Hospital Admissions and Bed Days in Children &lt;5 Years of Age in 7 European Countries
Authors: Wang Xin , Li You , Vazquez Fernandez Liliana , Teirlinck Anne C , Lehtonen Toni , van Wijhe Maarten , Stona Luca , Bangert Mathieu , Reeves Rachel M , Bøås Håkon , van Boven Michiel , Heikkinen Terho , Klint Johannesen Caroline , Baraldi Eugenio , Donà Daniele , Tong Sabine , Campbell Harry ,   Respiratory Syncytial Virus Consortium in Europe (RESCEU) Investigators, Reeves Rachel M , Li You , Wang Xin , Campbell Harry , Nair Harish , van Wijhe Maarten , Fischer Thea Kølsen , Simonsen Lone , Trebbien Ramona , Johannesen Caroline Klint , Tong Sabine , Bangert Mathieu , Demont Clarisse , Lehtonen Toni , Heikkinen Terho , Teirlinck Anne C , van Boven Michiel , van der Hoek Wim , van der Maas Nicoline , Meijer Adam , Fernandez Liliana Vazquez , Bøås Håkon , Bekkevold Terese , Flem Elmira , Stona Luca , Speltra Irene , Giaquinto Carlo , Baraldi Eugenio , Donà Daniele , Cheret Arnaud , Leach Amanda , Stoszek Sonia , Beutels Philippe , Bont Louis , Pollard Andrew , Openshaw Peter , Abram Michael , Swanson Kena , Rosen Brian , Molero Eva 
Published: November 2021

Abstract

Background
Respiratory syncytial virus (RSV) is a leading cause of respiratory tract infections (RTIs) in young children. High-quality country-specific estimates of bed days and length of stay (LOS) show the population burden of RSV-RTI on secondary care services and the burden among patients, and can be used to inform RSV immunization implementation decisions.

Methods
We estimated the hospital burden of RSV-associated RTI (RSV-RTI) in children under 5 years in 7 European countries (Finland, Denmark, Norway, Scotland, England, the Netherlands, and Italy) using routinely collected hospital databases during 2001–2018. We described RSV-RTI admission rates during the first year of life by birth month and assessed their correlation with RSV seasonality in 5 of the countries (except for England and Italy). We estimated average annual numbers and rates of bed days for RSV-RTI and other-pathogen RTI, as well as the hospital LOS.

Results
We found that infants born 2 months before the peak month of RSV epidemics more frequently had the highest RSV-RTI hospital admission rate. RSV-RTI hospital episodes accounted for 9.9–21.2 bed days per 1000 children aged &lt;5 years annually, with the median (interquartile range) LOS ranging from 2 days (0.5–4 days) to 4 days (2–6 days) between countries. Between 70% and 89% of these bed days were in infants aged &lt;1 year, representing 40.3 (95% confidence interval [CI], 40.1–40.4) to 91.2 (95% CI, 90.6–91.8) bed days per 1000 infants annually. The number of bed days for RSV-RTI was higher than that for RTIs associated with other pathogens in infants aged &lt;1 year, especially in those &lt;6 months.

Conclusions
RSV disease prevention therapies (monoclonal antibodies and maternal vaccines) for infants could help prevent a substantial number of bed days due to RSV-RTI. "High-risk" birth months should be considered when developing RSV immunization schedules. Variation in LOS between countries might reflect differences in hospital care practices.