Long-Term Effect Of COVID-19 on Children's Lung Function: A Prospective Longitudinal Study

Introduction-Aim: The study evaluates the long-term effect of COVID-19 on lung function in children, considering symptoms, physical examination findings, radiologic and laboratory evaluations during the acute infection period (AIP). Material and Methods: This prospective, longitudinal, multicenter study involved 270 patients with confirmed SARS-CoV-2 infection. Patients underwent pulmonary function tests (PFTs) (spirometry, diffusion capacity of the lung for carbon monoxide (DLCO), and plethysmography) at the 3rd and 6th months of follow-up. Clinical characteristics, radiological, and laboratory findings during AIP were analyzed to establish the relationship with PFT parameters on long-term follow-up. Results: The mean age was 12.97 ± 3.43 years (6–18 years), and 141(52.2%) were girls. Most patients had mild disease, while 193 patients were classified as having pneumonia. Overall mean PFT parameters were normal at the 3rd and 6th months, and FEV₁%, FVC%, and DLCOadj% showed statistically significant longitudinal changes. Abnormal DLCOadj was observed in patients with COVID-19 pneumonia at the 6th month when compared with the non-pneumonia group (p = 0.046). At the 3rd month follow-up, comorbidities were independently associated with abnormal FEV₁ (OR 6.30, 95% CI 2.61–15.17, p < 0.001) and abnormal FVC (OR 3.47, 95% CI 1.72–7.00, p < 0.001). Respiratory system related abnormal physical examination findings were also independently associated with abnormal FEV₁ (OR 3.04, 95% CI 1.13–8.21, p = 0.028). Dyspnea showed a borderline association with abnormal FVC (OR 2.11, 95% CI 0.98–4.54, p = 0.057). Pathologic chest radiography, interlobular septal thickening on thorax CT, ground-glass opacity, fever, dyspnea, and respiratory system related abnormal physical examination findings during the AIP were associated with abnormal PFT parameters during follow-up. Disease severity scores did not differ significantly between children with normal and abnormal. Conclusions: Most children had preserved mean pulmonary function during follow-up after SARS-CoV-2 infection. However, children with COVID-19 pneumonia, comorbidities, and respiratory system related abnormal physical examination findings during the AIP may be at increased risk for persistent functional abnormalities. Follow-up assessment in higher-risk children should include spirometry, and DLCO measurement should be considered when feasible.