Participants
Children (ages 29 days to 17 years) with confirmed COVID-19 infection prior to or during hospitalization (PCR, antigen, or IgG/IgM+) who underwent chest X-ray between admission and 72 hours after hospitalization were included in this sample. Chronic lung disease with possible confounding radiological findings (bronchiolitis obliterans, bronchopulmonary dysplasia, ciliary dyskinesia, tuberculosis, cystic fibrosis, congenital pulmonary malformations, intestinal disease, among others) was among the exclusion criteria. Also, chest-radiographs that could not be retrieved from the PACS system (Picture Achieving communication system) or that could not be found, were excluded from the reading list. For more information about data analysis X-ray selection flowchart, please see supplementary appendix 1.