Pulmonary function tests in the follow-up of children with COVID-19

The SARS-CoV-2 virus has infected more than 235 million people since it was accepted as a pandemic in March 2020. Although a milder disease is seen in the pediatric age group, the extent of lung damage and its long-term effects are still unknown. In this study, persistent respiratory symptoms and pulmonary function tests were investigated in children with COVID-19. Fifty children with a confirmed diagnosis of COVID-19 were included in the study. Patients were evaluated for ongoing respiratory symptoms and pulmonary function tests 3 months after infection. Patients with and without persistent symptoms were compared in terms of demographic, clinical, laboratory, and radiological characteristics and also disease severity. Three months after infection, persistent respiratory symptoms were found to be present in 28% of patients; cough, chest pain and tightness, dyspnea, and exertional dyspnea were the most common symptoms. Three patients had an obstructive deficit, and one had a restrictive deficit. Four patients had impaired diffusing capacity of the lungs for carbon monoxide (DLCO). A significant decrease in FEV1/FVC and an increase in lung clearance index were found in the patients with persistent respiratory symptoms. Persistent respiratory symptoms were present in 50% of patients who had severe disease and 12.5% with non-severe disease. DLCO was also significantly lower in the severe disease group.   Conclusions: Our study suggests that the persistence of respiratory symptoms is not related to the severity of acute COVID-19 in children. The inflammatory process due to COVID-19 may continue regardless of its severity, and consequently, peripheral airways may be affected. What is Known: • As compared with adults, children with COVID-19 exhibit a milder disease course and lower mortality rates. However, due to the lack of follow-up studies on children, the long-term effects of their contracting the disease are unknown. What is New: • Although COVID-19 has been thought to have a milder course in children, respiratory system symptoms persist in approximately 30% of patients 3 months after infection. The persistent respiratory symptoms suggest that the inflammatory process due to COVID-19 may continue in some children, even if the clinical findings at admission are not severe, and that the peripheral airways may be affected accordingly.