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

ABSTRACT 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 FEV 1 %, 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 FEV 1 (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 FEV 1 (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.