364 - Post-Pandemic Declines in Respiratory Support and Intensive-Care Utilization Among RSV-Positive Children: A Five-Year Adjusted Cohort Analysis

Publication Number: 2353.364

Mawada Abbaker, hurley medical center, Grand Blanc, MI, United States; Rashed Hasan, Michigan State University College of Human Medicine/Hurley Medical Center, Troy, MI, United States; Mawada Abbaker, Hurley Medical Center/Michigan State University, Flint, MI, United States

Background: The COVID-19 pandemic altered viral circulation patterns, yet the trajectory of respiratory syncytial virus (RSV)-associated disease severity after 2019 remains understudied. Quantifying changes in respiratory support and intensive-care use reveals evolving clinical phenotypes and informs future RSV preparedness.

Objective: To evaluate year-to-year changes in respiratory support, pediatric intensive care unit (PICU) admission, and physiologic parameters among RSV-positive children from 2019-2024, adjusted for age, sex, and co-infecting pathogens.

Design/Methods: Retrospective cohort study via chart review including children ≤ 18 years presenting with PCR-confirmed RSV infection between January 1, 2019, and December 31, 2024.ICD-10 based selection with each patient contributed one encounter per year.
Exposures: RSV season (2019-2024), with 2019 as the reference year.
Measures: Oxygen therapy, high-flow nasal cannula (HFNC), CPAP/BPAP, invasive mechanical ventilation (IMV), nebulization, and PICU admission. Physiologic outcomes included initial heart rate, respiratory rate, SpO₂, temperature, and WBC. Generalized estimating equations (GEE) and linear mixed models (LMM) were fit, adjusting for age, sex, overall coinfection, and seven specific pathogens (adenovirus, SARS-CoV-2, common human coronaviruses, human metapneumovirus, influenza, parainfluenza, Mycoplasma pneumoniae). False-discovery-rate (FDR) correction controlled for multiple comparisons. This study was IRB approved.

Results: Of 11 926 cases who presented to the emergency department with respiratory symmptoms, 8649 (72.5%) had at least one viral pathogen identified of which 2094 (17.6%) were RSV positive with a median (IQR) age of 14 (6-28) months. 54% were male, and 31% had ≥ 1 coinfection. Adjusted models demonstrated substantial declines in respiratory interventions versus 2019. Odds of mechanical ventilation were markedly reduced across 2020-2024 (log OR ≈ −1.2 to −4.8; q < 0.001). PICU admission, oxygen therapy, and nebulization similarly declined from 2021 onward (all q < 0.01). CPAP/BPAP use showed modest decreases in 2021 (q < 0.001) and 2024 (q < 0.05). Continuous physiologic measures revealed lower heart and respiratory rates and higher SpO₂ after 2020, consistent with milder presentations (Figure 1 and Figure 2).

Conclusion(s): Compared with 2019, RSV-positive encounters from 2020-2024 exhibited consistently lower adjusted odds of intensive respiratory support and PICU admission. Findings indicate sustained post-pandemic attenuation of RSV severity, possibly due to changes in host immunity, viral virulence, or management strategies.

Figure 1. Adjusted Odds of Severe Interventions Among RSV-Positive Encounters (vs 2019)
Heat map of adjusted log(OR) from GEE models comparing intervention use vs 2019. pink = lower odds; blue= higher; *p < 0.05, **p < 0.01, **p < 0.001. Odds of mechanical ventilation, PICU admission, and oxygen therapy were markedly reduced after 2020.

Figure 2. Adjusted Year-to-Year Differences in Physiologic Measures Among RSV-Positive Encounters (2019-2024)
Heat map of adjusted mean differences (vs 2019) in physiologic and lab variables among RSV-positive encounters (LMM). pink = lower; purple= higher; *p < 0.05, **p < 0.01, *p < 0.001. Heart rate and respiratory rates declined, while SpO₂ rose post-2019.