- A negative RT-PCR test for COVID-19 during the evaluation of the present illness - Extracorporeal membrane oxygenation (ECMO) - Pregnant or lactating women - Active underlying cancer treated with systemic chemotherapy or radiation therapy during the last 30 days - Transplantation of hematopoietic or solid organs - Chronic mechanical ventilation or dialysis - Otherwise unsuitable for study participation because of chronic, severe, end-stage, and life-limiting underlying disease unrelated to COVID-19 likely to interfere with management and assessment of acute pneumonia, only comfort or limited (non-aggressive) care is to be given, or life expectancy <6 months unrelated to acute COVID infection in the opinion of the Investigator

- A negative RT-PCR test for COVID-19 during the evaluation of the present illness - Extracorporeal membrane oxygenation (ECMO) - Pregnant or lactating women - Active underlying cancer treated with systemic chemotherapy or radiation therapy during the last 30 days - Transplantation of hematopoietic or solid organs - Chronic mechanical ventilation or dialysis - Otherwise unsuitable for study participation because of chronic, severe, end-stage, and life-limiting underlying disease unrelated to COVID-19 likely to interfere with management and assessment of acute pneumonia, only comfort or limited (non-aggressive) care is to be given, or life expectancy <6 months unrelated to acute COVID infection in the opinion of the Investigator