Lung Function Trajectories in Mild COVID-19 With 2-year Follow-up

Background The long-term pulmonary sequelae of mild coronavirus disease 2019 (COVID-19) remains unknown. In this study, we aimed to characterize lung function trajectories in individuals with mild COVID-19 from preinfection to 2 years postinfection.Methods We reinvited participants 2 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 dynamics in lung volumes in individuals with COVID-19 patients versus uninfected controls over two intervals: from pre-infection to 6 months postinfection and 6 months postinfection to 2 years postinfection.Results 52 individuals (48.6%) attended the 2-year examination at median 1.9 years (interquartile range, 1.8-2.4) after COVID-19, all with mild infection. Individuals with COVID-19 had an adjusted excess decline in forced expiratory volume in 1 second (FEV1) of 13.0 mL per year (95% confidence interval [CI], -23.5 to -2.5; P = .02) from before 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 (95% CI, -25.6-9.6; P = .40). A similar pattern was observed for forced vital capacity (FVC). Participants had a mean increase in diffusing capacity for carbon monoxide (DLco) of 3.33 (SD 7.97) between the 6- and 24-month examination.Conclusions Our results indicate that mild COVID-19 infection affects lung function at the time of infection with limited recovery 2 years after infection. This study assessed lung function prior to mild COVID-19 infection and up to 2 years after. It revealed a significant decline in the first 6 months after infection and a slower decline thereafter, indicating lasting decline, with limited recovery.