Hospitalizations Associated With Respiratory Syncytial Virus Illness Among Children and Adolescents in Ontario, Canada.

Background: Respiratory syncytial virus (RSV) illness poses a significant burden in children yet is understudied in those >2 years old.

Methods: We identified patients aged ≤17 years hospitalized with RSV between July 2010 and March 2023 using Ontario's administrative healthcare data. RSV-specific hospitalizations were defined by ICD-10-CA codes (B97.4, J12.1, J20.5, J21.0) and included overnight stays. Key outcomes included hospitalization frequency, intensive care unit (ICU) use, mechanical ventilation, supplemental oxygen, length of stay, mortality, and costs. Risk conditions included chronic respiratory diseases, congenital malformations, and cystic fibrosis.

Results: There were 23 930 RSV hospitalizations; annual counts ranged from 1356 (2010-2011) to 4298 (2022-2023). Children <2 years accounted for 84% of hospitalizations, though risk conditions were more common in those aged 2-17 years (35% vs. 7%). In 2022-2023, hospitalizations were ~2-fold, ~3-fold, and ~5-fold higher than previous years (2010-2021) for those <12 months, 12-<24 months, and 2-17 years, respectively. Median length of stay was 69 h. Annual median cost per hospitalization was $5070 (IQR: $4486-6742). ICU admission occurred in 12% of cases, with median costs over twice that of non-ICU stays ($12 042 vs. $5070). ICU use ranged from 7% to 16% in <2 years and 10%-35% in 2-17 years. In-hospital mortality was 0.12%, higher among those with risk conditions (<2 years: 0.61%; 2-17 years: 1.02%).

Conclusions: This study highlighted the burden associated with RSV hospitalizations for people aged ≤17 years and those who may be more impacted by RSV illness.