This paper presents the results of an observational, prospective study of the clinical progression and outcomes of patients with severe COVID-19. Overall, 260 patients with severe COVID-19 were included. The median age of the patients was 61 years (IQR 42.0-73.0), and 119 (45.8%) patients had one or more medical comorbidities. The median time from initial onset of symptoms to hospital admission was 8 days (IQR 6.0-11.0). Varying degrees of abnormalities in blood biochemical results were detected in most patients. All patients received supportive therapy and antiviral treatment. All patients were administered empirical antibiotic treatment with a median time of 5 days (IQR 3-7). Mechanical ventilation was required in accordance with respiratory conditions. At the data cutoff, 183 (70.4%) patients had been discharged, and 17 (6.5%) patients had been transferred to the intensive care unit (ICU). Twenty-five (9.6%) patients had died, and 35 (13.5%) patients were still in the hospital. During follow-up, 7 patients with fever were negative for SARS-Cov-2 antigens upon retest. The implications of the results are discussed for clinical features and the management of patients with severe COVID-19.