Trends in Hospitalisations Due to Respiratory Syncytial Virus in Swedish Children: A Nationwide Study 2010–2022

AIM: Respiratory syncytial virus (RSV) infection is a leading cause of paediatric hospitalisations. This study describes annual RSV-hospitalisation burden of disease, by gestational week of delivery, age and sex among children aged 0-17 years of age in Sweden, for the period 2010/11-2021/22. METHODS: Employing total population Swedish register data pertaining to hospitalisations due to RSV for the period 2010-2022. RESULTS: Over the study period a total of 26 772 children were hospitalised due to RSV. Most of the patients, 63.2%, were aged < 6 months and 39.9% were aged < 3 months. Among patients aged < 3 months, 88.5% were born at full term. The average number of hospital days increased with lower gestational age at birth for all age groups, except for patients aged 5- ≤ 17 years of age. Estimated incident rate ratios (IRR) comparing patients born at full term to patients born extremely preterm ranged between 2.43 and 1.75, respectively, for patients aged 0 < 3 months and 1 < 2 years of age. CONCLUSIONS: Paediatric RSV hospitalisations mostly occur in the youngest infants, and most are born at term. Gestational age at birth and age at admission are both negatively related to length of stay.