Study population
After institutional review board approval (0204-23-HMO), an observational case-control study was conducted. Given the retrospective nature of the study involving existing data, informed consent was exempted. Cases included infants who were referred for iPFT by a pediatric pulmonologist due to persistent respiratory complaints with a documented SARS-CoV-2 infection during their course of illness.
Controls included all infants who underwent iPFT at our medical center prior to the COVID-19 era (between 2008 and 2019). Demographic and clinical parameters of these patients were retrieved from computerized database. Excluded from the study were subjects with any diagnosis of chronic or congenital disease, including; extreme prematurity, chronic lung disease, congenital heart disease, pulmonary hypertension, Down’s syndrome, congenital diaphragmatic hernia, and infants who underwent iPFT testing prior to bone marrow transplant. We further excluded from the study infants in which the primary respiratory complaint for which they underwent a respiratory evaluation, was not documented in their medical file.