Background:The clinical course of coronavirus disease 2019 (COVID-19) varies distinctly. Particularly after severe or critical courses, i.e., after hospitalization, clinical manifestations frequently persist after the acute phase. However, symptoms may also persist after initially milder courses that can be treated in an outpatient setting. For patients who remain symptomatic after COVID-19, pulmonary rehabilitation (PR) is recommended. However, only few studies investigated the effectiveness of PR, especially considering different disease courses. The main objective was to evaluate the feasibility, safety, and efficacy of post-COVID-19 PR.Methods:A total of 120 post-COVID-19 patients who were referred to the Bad Reichenhall Clinic between April 2020 and January 2021 were asked to participate in this prospective observational study. PR was tailored to each patient’s individual needs and was based on the current recommendations. The primary outcome dyspnea was assessed with numerical rating scales and the modified Medical Research Council (mMRC) dyspnea scale. Secondary outcomes included other symptoms such as cough and sputum; physical capacity; lung function; fatigue; quality of life (QoL); depression; and anxiety. Furthermore, patients rated the overall effectiveness of PR and their subjective change in health status.Results:A total of 108 patients (mean age 55.6±10.1 years, 45.4% female) were included and were assigned to 3 groups depending on the referral mode (A: severe acute; B: severe after interval, C: mild after interval). At the end of PR, we detected improvements in the intensity of exertional dyspnea, physical capacity, QoL, fatigue, and depression in the overall group, with large effect sizes (Cohen’s d>0.8). Moderate effect sizes (0.5≤d<0.8) were found for resting dyspnea and the mMRC-dyspnea scale. Cohen’s d>0.4 was found for vital capacity, forced expiratory volume in one second, partial oxygen pressure, and anxiety. Significant but rather small effect sizes (0.2<d<0.4) were found for cough, sputum, pain, and other lung function parameters.Conclusions:PR is feasible, safe, and effective after acute COVID-19, which was true for all 3 groups analyzed, with a trend toward greater efficacy after severe courses of COVID-19 and an earlier start of PR after acute COVID-19. Therefore, all post-COVID-19 patients who remain symptomatic should be offered PR.Trial registration: German Clinical Trials Register, DRKS00023180. Registered 01 September 2020 – Retrospectively registered, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00023180