Eligibility Criteria

Adults with COVID-19 who required hospitalization. The case definition was a person with laboratory confirmation for COVID-19 infection, regardless of clinical signs and symptoms, according to RT-PCR SARS-CoV-2 (Amplification Kit Ref 09N77-090 according to Berlin protocol) in nasopharyngeal aspirate or swab. The criteria to define the need for hospitalization were applied by the physicians of the primary or emergency Health-Care Providing Institutions (IPS—Instituciones Prestadoras de Salud), based on the fulfillment of two or more of the following criteria: over 60 years of age, diabetes, cardiovascular disease (coronary artery disease or chronic heart failure), chronic lung disease (chronic obstructive pulmonary disease, emphysema, asthma), immunosuppression (prednisone > 20 mg/day for more than 14 days, methotrexate > 0.4 mg/kg/week, or biologic therapy), lymphopenia < 800 mm³, LDH > 350 IU/L, desaturation < 90%, hypoxemia with PAFI < 300 mm Hg, D-dimer > 1 mg/mL, elevated troponin I, EKG with prolonged QTc, ferritin > 1000 ng/mL, PCR > 10 mg/L, abnormal chest X-ray or computed tomography (basal consolidation, nodules, cavitation or pleural effusion).