Respiratory Syncytial Virus, Influenza, and Coronavirus Disease 2019 Hospitalizations in Children in Colorado During the 2021-2022 Respiratory Virus Season

J Pediatr. 2023 Sep:260:113491. doi: 10.1016/j.jpeds.2023.113491. Epub 2023 May 16.


Objective: To compare demographic characteristics, clinical features, and outcomes of children hospitalized with respiratory syncytial virus (RSV), influenza, or severe acute respiratory syndrome coronavirus 2 during their cocirculation 2021-2022 respiratory virus season.

Methods: We conducted a retrospective cohort study using Colorado's hospital respiratory surveillance data comparing coronavirus disease 2019 (COVID-19)-, influenza-, and RSV-hospitalized cases < 18 years of age admitted and undergoing standardized molecular testing between October 1, 2021, and April 30, 2022. Multivariable log-binomial regression modeling evaluated associations between pathogen type and diagnosis, intensive care unit admission, hospital length of stay, and highest level of respiratory support received.

Results: Among 847 hospitalized cases, 490 (57.9%) were RSV associated, 306 (36.1%) were COVID-19 associated, and 51 (6%) were influenza associated. Most RSV cases were <4 years of age (92.9%), whereas influenza hospitalizations were observed in older children. RSV cases were more likely to require oxygen support higher than nasal cannula compared with COVID-19 and influenza cases (P < .0001), although COVID-19 cases were more likely to require invasive mechanical ventilation than influenza and RSV cases (P < .0001). Using multivariable log-binomial regression analyses, compared with children with COVID-19, the risk of intensive care unit admission was highest among children with influenza (relative risk, 1.97; 95% CI, 1.22-3.19), whereas the risk of pneumonia, bronchiolitis, longer hospital length of stay, and need for oxygen were more likely among children with RSV.

Conclusions: In a season with respiratory pathogen cocirculation, children were hospitalized most commonly for RSV, were younger, and required higher oxygen support and non-invasive ventilation compared with children with influenza and COVID-19.

Keywords: COVID-19; RSV; bronchiolitis; croup; influenza; respiratory infection.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • COVID-19* / epidemiology
  • Child
  • Colorado / epidemiology
  • Hospitalization
  • Humans
  • Infant
  • Influenza, Human* / diagnosis
  • Oxygen
  • Respiratory Syncytial Virus Infections* / diagnosis
  • Respiratory Syncytial Virus Infections* / epidemiology
  • Respiratory Syncytial Virus Infections* / therapy
  • Respiratory Syncytial Virus, Human*
  • Retrospective Studies
  • Seasons


  • Oxygen