phase 1 will enroll adult patients (≥18 years of age), phase 2 will enroll adult patients, phase 3 will enroll adult patients and an additional adolescent cohort of patients (≥12 and \<18 years of age) key inclusion criteria: 1. for the adolescent cohort in phase 3 only: weighs ≥40 kg at randomization 2. has sars-cov-2-positive antigen or molecular diagnostic test (by validated sarscov-2 antigen, rt-pcr, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal \[np\], nasal, oropharyngeal \[op\], or saliva) ≤72 hours prior to randomization. a historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization 3. has symptoms consistent with covid-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe covid-19 as outlined in the exclusion criteria 4. maintains o2 saturation ≥93% on room air key

phase 1 will enroll adult patients (≥18 years of age), phase 2 will enroll adult patients, phase 3 will enroll adult patients and an additional adolescent cohort of patients (≥12 and \<18 years of age) key inclusion criteria: 1. for the adolescent cohort in phase 3 only: weighs ≥40 kg at randomization 2. has sars-cov-2-positive antigen or molecular diagnostic test (by validated sarscov-2 antigen, rt-pcr, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal \[np\], nasal, oropharyngeal \[op\], or saliva) ≤72 hours prior to randomization. a historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization 3. has symptoms consistent with covid-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe covid-19 as outlined in the exclusion criteria 4. maintains o2 saturation ≥93% on room air key

phase 1 will enroll adult patients (≥18 years of age), phase 2 will enroll adult patients phase 3 will enroll adult patients and an additional adolescent cohort of patients (≥12 and <18 years of age) key inclusion criteria: for the adolescent cohort in phase 3 only: weighs ≥40 kg at randomization has sars-cov-2-positive antigen or molecular diagnostic test (by validated sarscov- 2 antigen, rt-pcr, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal [np], nasal, oropharyngeal [op], or saliva) ≤72 hours prior to randomization. a historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization has symptoms consistent with covid-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe covid-19 as outlined in the exclusion criteria maintains o2 saturation ≥93% on room air key

phase 1 will enroll adult patients (≥18 years of age), phase 2 will enroll adult patients phase 3 will enroll adult patients and an additional adolescent cohort of patients (≥12 and <18 years of age) key inclusion criteria: for the adolescent cohort in phase 3 only: weighs ≥40 kg at randomization has sars-cov-2-positive antigen or molecular diagnostic test (by validated sarscov- 2 antigen, rt-pcr, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal [np], nasal, oropharyngeal [op], or saliva) ≤72 hours prior to randomization. a historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization has symptoms consistent with covid-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe covid-19 as outlined in the exclusion criteria maintains o2 saturation ≥93% on room air key

phase 1 will enroll adult patients (≥18 years of age), phase 2 will enroll adult patients phase 3 will enroll adult patients and an additional adolescent cohort of patients (≥12 and <18 years of age) key inclusion criteria: 1. for the adolescent cohort in phase 3 only: weighs ≥40 kg at randomization 2. has sars-cov-2-positive antigen or molecular diagnostic test (by validated sarscov- 2 antigen, rt-pcr, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal [np], nasal, oropharyngeal [op], or saliva) ≤72 hours prior to randomization. a historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization 3. has symptoms consistent with covid-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe covid-19 as outlined in the exclusion criteria 4. maintains o2 saturation ≥93% on room air key

phase 1 will enroll adult patients (≥18 years of age), phase 2 will enroll adult patients phase 3 will enroll adult patients and an additional adolescent cohort of patients (≥12 and <18 years of age) key inclusion criteria: 1. for the adolescent cohort in phase 3 only: weighs ≥40 kg at randomization 2. has sars-cov-2-positive antigen or molecular diagnostic test (by validated sarscov- 2 antigen, rt-pcr, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal [np], nasal, oropharyngeal [op], or saliva) ≤72 hours prior to randomization. a historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization 3. has symptoms consistent with covid-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe covid-19 as outlined in the exclusion criteria 4. maintains o2 saturation ≥93% on room air key