Lung function trajectories in mild COVID-19 with two-year follow-up.

OBJECTIVE:To characterize lung function dynamics in individuals with mild COVID-19 from pre-infection to two years post-infection. METHODS:We re-invited participants two years after infection from our matched cohort study of the Copenhagen General Population who had initially been examined 5.4 months after infection. We repeated lung tests and questionnaires. Linear mixed models were used to estimate lung volume changes in individuals with COVID-19 patients versus uninfected controls over two intervals: from pre-infection to six months post-infection and six months post-infection to two years post-infection. RESULTS:52 individuals (48.6%) attended the two-year examination at median 1.9 years (IQR 1.8; 2.4) after COVID-19, all with mild infection. Individuals with COVID-19 had an adjusted excess decline in FEV1 of 13.0 mL per year (CI 23.5; 2.5), p=0.02 from prior infection to 6 months after infection compared to uninfected controls. From 6 to 24 months after infection, they had an excess decline of 7.5 mL per year (CI 25.6; 9.6), p=0.40. A similar pattern was observed for FVC. Participants had a mean increase in DLco of 3.33 (SD 7.97) between the 6- and 24-month examination. CONCLUSION:Our results indicate that mild COVID-19 infection affects lung function at time of infection with limited recovery two years after infection.