Clinical Research Directory

Inclusion Criteria: * Age ≥ 18 years, patients with a suspected diagnosis of post/long-COVID-19 syndrome who present to our pneumology or infectious disease outpatient clinic or corresponding ward from the start of the study and whose SARS-CoV-2 infection was diagnosed at least 3 and not longer than 18 months prior to presentation * Patients at least 3 and not longer than 18 months after a SARS-CoV-2 infection without post/long-COVID-19 syndrome who present to our post-infection outpatient clinic for follow-up Exclusion Criteria: * Patients who refuse to participate in the study * Severe underlying chronic pulmonary, cardiac, or systemic disease (e.g., Chronic obstructive pulmonary disease (COPD), severe heart failure, neuromuscular disease) that was diagnosed prior to acute COVID-19 disease and whose progression appears likely as the cause of dyspnea * Other non pneumologic causes of dyspnea (e.g., hemoglobin \< 100 g/L) * Unstable or acute disease (e.g., acute infection, acute renal failure, acute coronary syndrome) * Inability to perform spiroergometry, including transient orthopedic problems, contraindications to central venous and arterial catheter placement (e.g., severe bleeding tendency).