Each participant must meet all of the following criteria to be enrolled in this <br/ > study: <br/ > 1. Age: <br/ > a. Phase 2: Is an adult aged 18 years and above <br/ > b. Phase 3: Is an adult aged 18 years and above or is an adolescent aged 12 to <br/ > 17 years (inclusive) and weighing �40 kg at the time of screening <br/ > Note: Adolescent enrollment will open only upon sponsor communication to sites <br/ > after review of Phase 2 data by the iDMC. <br/ > 2. Has had SARS-CoV-2 positive antigen, RT-PCR, or other locally approved molecular <br/ > diagnostic assay obtained within 5 days prior to randomization. <br/ > Note: A historical record of a positive result from a test conducted within 5 days prior to <br/ > randomization is acceptable. SARS-CoV-2 antibody testing cannot be used for study <br/ > eligibility. <br/ > 3. Has had initial onset of one or more of the following self-reported COVID-19-related <br/ > signs or symptoms within 5 days prior to randomization: <br/ > a. measured temperature �38°C (100.4°F) <br/ > b. subjective fever (feeling hot or feverish) <br/ > c. chills (shivering) <br/ > d. cough <br/ > e. sore throat <br/ > f. congestion (stuffy or runny nose) <br/ > g. shortness of breath or difficulty breathing with exertion worse than usual <br/ > h. muscle or body aches <br/ > i. fatigue (low energy or tiredness) <br/ > j. headache <br/ > k. loss of taste or smell <br/ > l. nausea or vomiting <br/ > m. diarrhea <br/ > 4. Has one or more of the following COVID-19-related signs or symptoms on the day of <br/ > randomization: <br/ > a. measured temperature �38°C (100.4°F) <br/ > b. subjective fever (feeling hot or feverish) <br/ > c. chills (shivering) <br/ > d. cough <br/ > e. sore throat <br/ > f. congestion (stuffy or runny nose) <br/ > g. shortness of breath or difficulty breathing with exertion worse than usual <br/ > h. muscle or body aches <br/ > i. fatigue (low energy or tiredness) <br/ > j. headache <br/ > k. loss of taste or smell <br/ > l. nausea or vomiting <br/ > m. diarrhea <br/ > 5. Is at high risk of disease progression defined as: <br/ > a. Age >55 years <br/ > b. Age 18 to �55 years with one or more preexisting medical conditions as follows <br/ > i. Obesity (body mass index [BMI] �30 kg/m2) <br/ > ii. Diabetes (Type 1 or Type 2) <br/ > iii. Chronic kidney disease (eGFR calculated by Modification of Diet in Renal <br/ > Disease [MDRD] of 59 mL/min/1.73 m2 or less, including end-stage renal <br/ > disease on hemodialysis) <br/ > iv. Chronic lung disease (emphysema/chronic obstructive pulmonary disease, <br/ > chronic bronchitis, interstitial lung disease [including idiopathic <br/ > pulmonary fibrosis] or cystic fibrosis) <br/ > v. Cardiac disease (heart failure, coronary artery disease, or <br/ > cardiomyopathies) <br/ > vi. Sickle cell disease or thalassemia <br/ > vii. Solid organ or blood stem cell transplant recipients <br/ > viii. Other immunodeficiency due to underlying illness or immunosuppressant <br/ > medication (eg, corticosteroids �20 mg/day prednisone or equivalent) <br/ > ix. Down Syndrome <br/ > x. Stroke or cerebrovascular disease, which affects blood flow to the brain <br/ > xi. Substance use disorder <br/ > xii. Pregnant (Phase 3 only, Enrollment of participants who are pregnant may <br/ > only open upon sponsor communication to sites after review of Phase 2 <br/ > data by the iDMC) <br

Each participant must meet all of the following criteria to be enrolled in this <br/ > study: <br/ > 1. Age: <br/ > a. Phase 2: Is an adult aged 18 years and above <br/ > b. Phase 3: Is an adult aged 18 years and above or is an adolescent aged 12 to <br/ > 17 years (inclusive) and weighing �40 kg at the time of screening <br/ > Note: Adolescent enrollment will open only upon sponsor communication to sites <br/ > after review of Phase 2 data by the iDMC. <br/ > 2. Has had SARS-CoV-2 positive antigen, RT-PCR, or other locally approved molecular <br/ > diagnostic assay obtained within 5 days prior to randomization. <br/ > Note: A historical record of a positive result from a test conducted within 5 days prior to <br/ > randomization is acceptable. SARS-CoV-2 antibody testing cannot be used for study <br/ > eligibility. <br/ > 3. Has had initial onset of one or more of the following self-reported COVID-19-related <br/ > signs or symptoms within 5 days prior to randomization: <br/ > a. measured temperature �38°C (100.4°F) <br/ > b. subjective fever (feeling hot or feverish) <br/ > c. chills (shivering) <br/ > d. cough <br/ > e. sore throat <br/ > f. congestion (stuffy or runny nose) <br/ > g. shortness of breath or difficulty breathing with exertion worse than usual <br/ > h. muscle or body aches <br/ > i. fatigue (low energy or tiredness) <br/ > j. headache <br/ > k. loss of taste or smell <br/ > l. nausea or vomiting <br/ > m. diarrhea <br/ > 4. Has one or more of the following COVID-19-related signs or symptoms on the day of <br/ > randomization: <br/ > a. measured temperature �38°C (100.4°F) <br/ > b. subjective fever (feeling hot or feverish) <br/ > c. chills (shivering) <br/ > d. cough <br/ > e. sore throat <br/ > f. congestion (stuffy or runny nose) <br/ > g. shortness of breath or difficulty breathing with exertion worse than usual <br/ > h. muscle or body aches <br/ > i. fatigue (low energy or tiredness) <br/ > j. headache <br/ > k. loss of taste or smell <br/ > l. nausea or vomiting <br/ > m. diarrhea <br/ > 5. Is at high risk of disease progression defined as: <br/ > a. Age >55 years <br/ > b. Age 18 to �55 years with one or more preexisting medical conditions as follows <br/ > i. Obesity (body mass index [BMI] �30 kg/m2) <br/ > ii. Diabetes (Type 1 or Type 2) <br/ > iii. Chronic kidney disease (eGFR calculated by Modification of Diet in Renal <br/ > Disease [MDRD] of 59 mL/min/1.73 m2 or less, including end-stage renal <br/ > disease on hemodialysis) <br/ > iv. Chronic lung disease (emphysema/chronic obstructive pulmonary disease, <br/ > chronic bronchitis, interstitial lung disease [including idiopathic <br/ > pulmonary fibrosis] or cystic fibrosis) <br/ > v. Cardiac disease (heart failure, coronary artery disease, or <br/ > cardiomyopathies) <br/ > vi. Sickle cell disease or thalassemia <br/ > vii. Solid organ or blood stem cell transplant recipients <br/ > viii. Other immunodeficiency due to underlying illness or immunosuppressant <br/ > medication (eg, corticosteroids �20 mg/day prednisone or equivalent) <br/ > ix. Down Syndrome <br/ > x. Stroke or cerebrovascular disease, which affects blood flow to the brain <br/ > xi. Substance use disorder <br/ > xii. Pregnant (Phase 3 only, Enrollment of participants who are pregnant may <br/ > only open upon sponsor communication to sites after review of Phase 2 <br/ > data by the iDMC) <br