key inclusion criteria: * willing and able to provide written informed consent, or with a legal representative who can provide informed consent * sars-cov-2 infection first confirmed by polymerase chain reaction (pcr) (parts a and b) or by nucleic acid testing or direct antigen testing (part c) with sample collected ≤ 4 days prior to randomization * covid-19 symptom onset ≤ 7 days prior to randomization * oxygen saturation as measured by pulse oximetry (spo2) \> 94% on room air key

key inclusion criteria: * willing and able to provide written informed consent, or with a legal representative who can provide informed consent * sars-cov-2 infection first confirmed by polymerase chain reaction (pcr) (parts a and b) or by nucleic acid testing or direct antigen testing (part c) with sample collected ≤ 4 days prior to randomization * covid-19 symptom onset ≤ 7 days prior to randomization * oxygen saturation as measured by pulse oximetry (spo2) \> 94% on room air key

key inclusion criteria: willing and able to provide written informed consent, or with a legal representative who can provide informed consent sars-cov-2 infection first confirmed by polymerase chain reaction (pcr) (parts a and b) or by nucleic acid testing or direct antigen testing (part c) with sample collected ≤ 4 days prior to randomization covid-19 symptom onset ≤ 7 days prior to randomization oxygen saturation as measured by pulse oximetry (spo2) > 94% on room air key

key inclusion criteria: willing and able to provide written informed consent, or with a legal representative who can provide informed consent sars-cov-2 infection first confirmed by polymerase chain reaction (pcr) (parts a and b) or by nucleic acid testing or direct antigen testing (part c) with sample collected ≤ 4 days prior to randomization covid-19 symptom onset ≤ 7 days prior to randomization oxygen saturation as measured by pulse oximetry (spo2) > 94% on room air key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent - severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection first confirmed by polymerase chain reaction (pcr) (parts a and b) or by nucleic acid testing or direct antigen testing (part c) with sample collected ≤ 4 days prior to randomization - coronavirus disease 2019 (covid-19) symptom onset ≤ 7 days prior to randomization - oxygen saturation as measured by pulse oximetry (spo2) > 94% on room air key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent - severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection first confirmed by polymerase chain reaction (pcr) (parts a and b) or by nucleic acid testing or direct antigen testing (part c) with sample collected ≤ 4 days prior to randomization - coronavirus disease 2019 (covid-19) symptom onset ≤ 7 days prior to randomization - oxygen saturation as measured by pulse oximetry (spo2) > 94% on room air key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent - severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection first confirmed by polymerase chain reaction (pcr) ≤ 4 days prior to randomization - presence of ≥ 1 symptom(s) consistent with coronavirus disease 2019 (covid-19) for ≤ 7 days prior to randomization (fever, cough, fatigue, shortness of breath, sore throat, headache, myalgia/arthralgia) - oxygen saturation as measured by pulse oximetry (spo2) > 94% on room air key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent - severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infection first confirmed by polymerase chain reaction (pcr) ≤ 4 days prior to randomization - presence of ≥ 1 symptom(s) consistent with coronavirus disease 2019 (covid-19) for ≤ 7 days prior to randomization (fever, cough, fatigue, shortness of breath, sore throat, headache, myalgia/arthralgia) - oxygen saturation as measured by pulse oximetry (spo2) > 94% on room air key