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Original research
Clinical definition of respiratory viral infections in young children and potential bronchiolitis misclassification
  1. Rosemary Megalaa1,
  2. Geovanny F Perez1,2,3,4,
  3. Sasikumar Kilaikode-Cheruveettara1,
  4. Nidhi Kotwal1,
  5. Carlos E Rodriguez-Martinez5,6,7,
  6. Gustavo Nino1,2,3,4
  1. 1 Division of Pulmonary and Sleep Medicine, Children’s National Medical Center, Washington, District of Columbia, USA
  2. 2 Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
  3. 3 Department of Integrative Systems Biology, Center for Genetic Medicine Research, George Washington University, Washington, District of Columbia, USA
  4. 4 Center for Genetic Research Medicine, Children’s National Medical Center, Washington, District of Columbia, USA
  5. 5 Department of Pediatrics, School of Medicine, Universidad Nacional de Colombia, Bogota, Colombia
  6. 6 Department of Pediatric Pulmonology and Pediatric Critical Care Medicine, School of Medicine, Universidad El Bosque, Bogota, Colombia
  7. 7 Research Unit, Military Hospital of Colombia, Bogota, Colombia
  1. Correspondence to Dr Gustavo Nino, Division of Pediatric Pulmonology and Sleep Medicine, Children’s National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington, DC 20010, USA; gnino{at}


Viral respiratory infections are often grouped as a single respiratory syndrome named ‘viral bronchiolitis’, independently of the viral etiology or individual risk factors. Clinical trials and guidelines have used a more stringent definition of viral bronchiolitis, including only the first episode of wheezing in children less than 12 months of age without concomitant respiratory comorbidities. There is increasing evidence suggesting that this definition is not being followed by pediatric care providers, but it is unclear to what extent viral respiratory infections are currently misclassified as viral bronchiolitis using standard definitions. We conducted a retrospective analysis of hospitalized young children (≤3 years) due to viral respiratory infections. Bronchiolitis was defined as the first wheezing episode less than 12 months of age. Demographic variables and comorbidities were obtained by electronic medical record review. The study comprised a total of 513 hospitalizations (n=453). Viral bronchiolitis was diagnosed in 144 admissions (28.1%). Notably, we identified that the majority of children diagnosed with bronchiolitis (63%) were misclassified as they had prior episodes of wheezing. Many children with bronchiolitis misclassification had significant comorbidities, including prematurity (51%), neuromuscular conditions (9.8%), and congenital heart disease (9.8%). Misclassification of bronchiolitis is a common problem that may lead to inappropriate management of viral respiratory infections in young children. A comprehensive approach that takes into consideration viral etiology and individual risk factors may lead to a more accurate clinical assessment of this condition and would potentially prevent bronchiolitis misclassification.

  • bronchiolitis
  • infants
  • viral respiratory infections
  • prematurity

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  • Contributors Each author had the following contributions: inception of the concept of the original work, data collection, data analysis, writing the manuscript, editing the manuscript, and literature review.

  • Funding This work is supported by grant nos NHLBI/HL090020 (K12 Genomics of Lung), NICHC/HD001399 (K12 Child Health Research Career Development Award), and UL1TR000075 KL2TR000076 Awards from the NIH National Center for Advancing Translational Sciences.

  • Competing interests None declared.

  • Ethics approval Institutional Review Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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