ABSTRACT
Objective Asesmentof lung function impairment after mild SARS-CoV-2 infection in non-hospitalized children and adults. Additionally focusing on previous and persistent symptoms due to Covid-19 as well as current respiratory tract infection status. Methods Patients aged 6-60 years were recruited by telephone after laboratory-confirmed positive PCR result for SARS-CoV-2. Excluding criteria were hospitalization during Covid-19, pre-existing lung diseases (bronchial asthma, COPD) and smoking within the last five years. Pulmonary function testing was performed 4-12 weeks after infection, including Multiple-breath washout (LCI), spirometry (FEV?, FVC, Tiffeneau-Index) and diffusion capacity testing (DLCO, TLC;Hb corrected). All patients answered a questionnaire regarding previous and persistent symptoms. To gather information about the current infection status, a pharyngeal swab was taken to detect common respiratory bacterial and viral pathogens using a multiplex PCR approach. Patients with abnormalities in pulmonary function were invited to a follow up testing three months later. Results 110 patients, 90 adults and 20 children, were included. 44 adults and 17 children had at least one abnormal value in pulmonary function tests after an average of 7.7 weeks (range 4.3-11.3) to confirmed SARS-Cov-2 infection. Among these 44 adults, 33 reported pulmonary symptoms during Covid-19 and 19 persistent respiratory symptoms. No abnormalities in DLCO were found in adults. At the second pulmonary function testing 12.5 weeks (range 11.0-16.7) on average after the first appointment, improvement was shown in 61,7% ( n=29 of 47) with previous abnormal LCI, in 69,2% (n=9 of 13) with prior abnormal FVC and in 4 of 5 children with abnormal DLCO. No large correlation was detected between impaired pulmonary function and multiplex PCR results. Conclusion Mild lung function impairment was shown at the first appointment, particularly in LCI, but not equally measured in the entirety of lung function tests. Pulmonary function results were not affected by current infection status and partially mismatching with stated persisting symptoms. Within 3 months, most initially abnormal values improved, and self- perceived health status increased. Long term pulmonary function impairment was rarely detected after mild, non-hospitalized Covid-19 course. .