inclusion criteria: * able and willing to provide written informed consent * willing and able to comply with all study procedures. * confirmed infection with sars-cov-2 virus at or before the baseline visit by polymerase chain reaction (pcr) testing * ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the sars-cov-2 virus * hospitalization at the time of the baseline visit * ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 l/min by nasal cannula at the baseline visit * radiographic (x-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with covid-19 at screening or baseline, per the judgment of the investigator * clinical syndrome consistent with covid-19 at screening, per the judgment of the investigator (cdc 2020) * crp at screening \>15 mg/l (i.e., \>1.5 mg/dl) on local laboratory testing * agrees to practice an approved method of birth control

inclusion criteria: * able and willing to provide written informed consent * willing and able to comply with all study procedures. * confirmed infection with sars-cov-2 virus at or before the baseline visit by polymerase chain reaction (pcr) testing * ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the sars-cov-2 virus * hospitalization at the time of the baseline visit * ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 l/min by nasal cannula at the baseline visit * radiographic (x-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with covid-19 at screening or baseline, per the judgment of the investigator * clinical syndrome consistent with covid-19 at screening, per the judgment of the investigator (cdc 2020) * crp at screening \>15 mg/l (i.e., \>1.5 mg/dl) on local laboratory testing * agrees to practice an approved method of birth control

inclusion criteria: able and willing to provide written informed consent willing and able to comply with all study procedures. confirmed infection with sars-cov-2 virus at or before the baseline visit by polymerase chain reaction (pcr) testing ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the sars-cov-2 virus hospitalization at the time of the baseline visit ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 l/min by nasal cannula at the baseline visit radiographic (x-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with covid-19 at screening or baseline, per the judgment of the investigator clinical syndrome consistent with covid-19 at screening, per the judgment of the investigator (cdc 2020) crp at screening >15 mg/l (i.e., >1.5 mg/dl) on local laboratory testing agrees to practice an approved method of birth control

inclusion criteria: able and willing to provide written informed consent willing and able to comply with all study procedures. confirmed infection with sars-cov-2 virus at or before the baseline visit by polymerase chain reaction (pcr) testing ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the sars-cov-2 virus hospitalization at the time of the baseline visit ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 l/min by nasal cannula at the baseline visit radiographic (x-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with covid-19 at screening or baseline, per the judgment of the investigator clinical syndrome consistent with covid-19 at screening, per the judgment of the investigator (cdc 2020) crp at screening >15 mg/l (i.e., >1.5 mg/dl) on local laboratory testing agrees to practice an approved method of birth control

inclusion criteria: - able and willing to provide written informed consent - willing and able to comply with all study procedures - age ≥50 years at time of screening - confirmed infection with sars-cov-2 virus at or before the baseline visit by polymerase chain reaction (pcr) testing - ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the sars-cov-2 virus - hospitalization at the time of the baseline visit - ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 l/min by nasal cannula at the baseline visit - radiographic (x-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with covid-19 at screening or baseline, per the judgment of the investigator - clinical syndrome consistent with covid-19 at screening, per the judgment of the investigator (cdc 2020) - crp at screening >15 mg/l (i.e., >1.5 mg/dl) on local laboratory testing - agrees to practice an approved method of birth control

inclusion criteria: - able and willing to provide written informed consent - willing and able to comply with all study procedures - age ≥50 years at time of screening - confirmed infection with sars-cov-2 virus at or before the baseline visit by polymerase chain reaction (pcr) testing - ≤7 days to the time of randomization from the time of collection of the specimen that tested positive for the sars-cov-2 virus - hospitalization at the time of the baseline visit - ≥90% oxygen saturation on room air and/or ≥94% oxygen saturation on oxygen administration at 2 l/min by nasal cannula at the baseline visit - radiographic (x-ray or computed tomography scan, per local standard of care) and/or clinical evidence of pulmonary involvement consistent with covid-19 at screening or baseline, per the judgment of the investigator - clinical syndrome consistent with covid-19 at screening, per the judgment of the investigator (cdc 2020) - crp at screening >15 mg/l (i.e., >1.5 mg/dl) on local laboratory testing - agrees to practice an approved method of birth control