Bronchiolitis Post Introduction of RSV Immunoprophylaxis: Shifting Patterns in Pediatric Hospitalizations

Area of Science:

• Pediatrics
• Infectious Diseases
• Public Health Surveillance

Background:

• Bronchiolitis is a primary cause of infant hospitalization, frequently linked to respiratory syncytial virus (RSV).
• Post-pandemic monitoring of bronchiolitis trends is crucial for public health planning, especially with new RSV immunoprophylaxis.
• Understanding epidemiological shifts is vital for resource allocation and clinical strategy development.

Purpose of the Study:

• To analyze trends in pediatric bronchiolitis epidemiology.
• To assess changes in emergency department (ED) visits, hospitalizations, and intensive care unit (ICU) admissions for bronchiolitis.
• To evaluate the increase in respiratory syncytial virus (RSV) testing rates among affected children.

Main Methods:

• Retrospective cohort study of children aged ≤ 24 months presenting with bronchiolitis.
• Data collected during RSV seasons (October-April) from 2018-2019 to 2024-2025, excluding 2020-2022.
• Analysis of 12,741 patient records, including RSV testing and disposition outcomes.

Main Results:

• Bronchiolitis represented 6.2% of ED visits in 2024-2025, an increase from ~4% in prior seasons.
• Hospitalization rates for bronchiolitis declined despite increased ED presentations; ICU admission rates remained stable.
• RSV testing among bronchiolitis patients rose from 35.8% in 2018-2019 to 59.3% in 2024-2025.

Conclusions:

• Significant shifts in bronchiolitis epidemiology are evident, characterized by increased ED visits but decreased hospitalization proportions.
• The rise in RSV testing reflects evolving diagnostic practices and surveillance capabilities.
• Ongoing surveillance and adaptable clinical planning are essential to manage pediatric respiratory illness effectively.