Pulmonary function changes in pediatric patients following non-pneumonic COVID-19 infection

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is generally milder in children than adults, but concerns remain regarding potential long-term pulmonary sequelae, even in non-pneumonic cases. The aim of the study was to evaluate pulmonary function in children during acute COVID-19 and at three months post-infection, comparing findings with age- and sex-matched controls without COVID-19. Methods In this retrospective case–control study, with three-month follow-up, 120 children aged 5–18 years were enrolled: 60 with RT-PCR-confirmed acute COVID-19 without radiologic pneumonia and 60 age- and sex-matched controls with upper respiratory tract infection (URTI) but negative for SARS-CoV-2. Demographics, clinical symptoms, laboratory data, and pulmonary function tests (FVC%, FEV₁%, FEV₁/FVC) were collected during acute infection and at 3-month follow-up. Results The COVID-19 group had longer illness duration (p < 0.001), higher CRP (p = 0.038), and lower lymphocyte counts (p = 0.037). Common symptoms included fatigue (80%), fever (71.7%), and cough (51.7%). Spirometry parameters showed no significant differences between controls, acute COVID-19 cases, and 3-month follow-up cases. Specifically, FVC values were 93.12 ± 5.47 in controls, 91.10 ± 5.56 in acute cases, and 91.72 ± 4.75 at follow-up (P1 = 0.061, P2 = 0.348, P3 = 0.531). FEV₁ values were 85.44 ± 5.95, 83.47 ± 5.01, and 84.27 ± 7.98, respectively (all p > 0.05), while FEV₁/FVC ratios were 0.93 ± 0.06, 0.92 ± 0.08, and 0.93 ± 0.07 (all p > 0.05). No significant differences were also observed between asthmatic and non-asthmatic children in any spirometric parameter at acute infection or follow-up (all p > 0.05). Conclusion Mild COVID-19 in children does not appear to be associated with significant impairment in spirometric parameters during the acute phase or at three-month follow-up. Additionally, underlying asthma does not seem to influence these outcomes. However, these findings are limited to spirometric assessment and a relatively short follow-up period. Larger multicenter studies with longer follow-up and inclusion of more severe cases are needed to further evaluate long-term respiratory sequelae in pediatric populations.