Inclusion Criteria:  The prospective controlled randomized study included patients who presented to the emergency department of Erzurum Regional Training and Research Hospital with history of travel abroad within the last 14 days or contact with a confirmed or suspected COVID-19 patient and had recent complaints of fever, cough, dyspnea, malaise, and sudden loss of taste and smell. Patients regarded as high risk for COVID-19 underwent standard high-resolution computed tomography (HRCT). Predominantly peripheral bilateral ground glass opacities, subsegmental consolidation or linear opacities, crazy-paving pattern, and reverse halo sign were considered typical HRCT findings for COVID-19. Patients with these findings and patients with radiologically atypical findings but consistent clinical symptoms were hospitalized with suspected COVID-19. The diagnosis was confirmed by SARS-CoV-2 real-time polymerase chain reaction (PCR) testing of nasopharyngeal swab samples.  Exclusion Criteria:  Patients with any potential contraindications to pulmonary function testing (recent myocardial infarction, pulmonary embolism, cerebral aneurysm, active hemoptysis, pneumothorax, nausea/vomiting, recent thoracic, abdominal, or ocular surgery) were excluded before testing. In addition, patients who developed ARDS or MAS associated with secondary bacterial infection during the first week of treatment were also excluded.