- require mechanical ventilation or anticipated impending need for mechanical ventilation - received convalescent covid-19 plasma treatment prior to enrollment - were resident in a nursing home or long-term care facility immediately prior to current hospitalization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking investigational product - have an oxygen saturation (spo2) less than (<)88 percent (%) while breathing room air at rest at randomization.

- require mechanical ventilation or anticipated impending need for mechanical ventilation - received convalescent covid-19 plasma treatment prior to enrollment - were resident in a nursing home or long-term care facility immediately prior to current hospitalization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking investigational product - have an oxygen saturation (spo2) less than (<)88 percent (%) while breathing room air at rest at randomization.