inclusion criteria: * positive sars-cov-2 test conducted ≤ 5 days prior to randomization * mild or moderate covid-19 with symptom onset ≤ 5 days before randomization and at least one covid-19 related symptom present at time of screening * subject must be high risk, defined below: 1. age ≥70 years or 2. age ≥55 years with one of the following: i) obesity (body mass index \[bmi\] ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or 3. age 50 to 54 years with two of the following: i) obesity (bmi ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or 4. age ≥18 years with one of the following: i) down syndrome, sickle cell disease, dementia, parkinson's disease, or care home residents ii) one of the following immunocompromising conditions or immunosuppressive treatments: receiving chemotherapy for cancer, hematologic malignancy, being within 2 years of a hematopoietic stem cell transplant, receipt of a solid organ transplant and on immunosuppressive therapy, human immunodeficiency virus (hiv) infection untreated or with cd4+ t lymphocyte count \<350 cells per cubic millimeter, moderate/severe primary immunodeficiency, taking immunosuppressive medications * use of adequate contraception for females of childbearing potential

inclusion criteria: * positive sars-cov-2 test conducted ≤ 5 days prior to randomization * mild or moderate covid-19 with symptom onset ≤ 5 days before randomization and at least one covid-19 related symptom present at time of screening * subject must be high risk, defined below: 1. age ≥70 years or 2. age ≥55 years with one of the following: i) obesity (body mass index \[bmi\] ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or 3. age 50 to 54 years with two of the following: i) obesity (bmi ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or 4. age ≥18 years with one of the following: i) down syndrome, sickle cell disease, dementia, parkinson's disease, or care home residents ii) one of the following immunocompromising conditions or immunosuppressive treatments: receiving chemotherapy for cancer, hematologic malignancy, being within 2 years of a hematopoietic stem cell transplant, receipt of a solid organ transplant and on immunosuppressive therapy, human immunodeficiency virus (hiv) infection untreated or with cd4+ t lymphocyte count \<350 cells per cubic millimeter, moderate/severe primary immunodeficiency, taking immunosuppressive medications * use of adequate contraception for females of childbearing potential

inclusion criteria: positive sars-cov-2 test conducted ≤ 5 days prior to randomization mild or moderate covid-19 with symptom onset ≤ 5 days before randomization and at least one covid-19 related symptom present at time of screening subject must be high risk, defined below: age ≥70 years or age ≥55 years with one of the following: i) obesity (body mass index [bmi] ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or age 50 to 54 years with two of the following: i) obesity (bmi ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or age ≥18 years with one of the following: i) down syndrome, sickle cell disease, dementia, parkinson's disease, or care home residents ii) one of the following immunocompromising conditions or immunosuppressive treatments: receiving chemotherapy for cancer, hematologic malignancy, being within 2 years of a hematopoietic stem cell transplant, receipt of a solid organ transplant and on immunosuppressive therapy, human immunodeficiency virus (hiv) infection untreated or with cd4+ t lymphocyte count <350 cells per cubic millimeter, moderate/severe primary immunodeficiency, taking immunosuppressive medications use of adequate contraception for females of childbearing potential

inclusion criteria: positive sars-cov-2 test conducted ≤ 5 days prior to randomization mild or moderate covid-19 with symptom onset ≤ 5 days before randomization and at least one covid-19 related symptom present at time of screening subject must be high risk, defined below: age ≥70 years or age ≥55 years with one of the following: i) obesity (body mass index [bmi] ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or age 50 to 54 years with two of the following: i) obesity (bmi ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or age ≥18 years with one of the following: i) down syndrome, sickle cell disease, dementia, parkinson's disease, or care home residents ii) one of the following immunocompromising conditions or immunosuppressive treatments: receiving chemotherapy for cancer, hematologic malignancy, being within 2 years of a hematopoietic stem cell transplant, receipt of a solid organ transplant and on immunosuppressive therapy, human immunodeficiency virus (hiv) infection untreated or with cd4+ t lymphocyte count <350 cells per cubic millimeter, moderate/severe primary immunodeficiency, taking immunosuppressive medications use of adequate contraception for females of childbearing potential

inclusion criteria: positive sars-cov-2 test conducted ≤ 5 days prior to randomization mild or moderate covid-19 with symptom onset ≤ 5 days before randomization and at least one covid-19 related symptom present at time of screening subject must be high risk, defined below: age ≥80 years or age ≥65 years with one of the following: i) obesity (body mass index [bmi] ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or age ≥18 years with one of the following: i) down syndrome, sickle cell disease, dementia, parkinson's disease, or care home residents ii) one of the following immunocompromising conditions or immunosuppressive treatment: receiving chemotherapy or other therapies for cancer, hematologic malignancy, being within 2 years from receiving a hematopoietic stem cell or at any time following a solid organ transplant, human immunodeficiency virus (hiv) infection untreated or with cd4+ t lymphocyte count <350 cells per cubic millimeter within the past 6 months, combined primary immunodeficiency disorder, taking immunosuppressive medications use of adequate contraception for females of childbearing potential

inclusion criteria: positive sars-cov-2 test conducted ≤ 5 days prior to randomization mild or moderate covid-19 with symptom onset ≤ 5 days before randomization and at least one covid-19 related symptom present at time of screening subject must be high risk, defined below: age ≥80 years or age ≥65 years with one of the following: i) obesity (body mass index [bmi] ≥30 kg/m2) ii) diabetes mellitus iii) cardiovascular disease or hypertension iv) chronic lung disease requiring routine therapy or age ≥18 years with one of the following: i) down syndrome, sickle cell disease, dementia, parkinson's disease, or care home residents ii) one of the following immunocompromising conditions or immunosuppressive treatment: receiving chemotherapy or other therapies for cancer, hematologic malignancy, being within 2 years from receiving a hematopoietic stem cell or at any time following a solid organ transplant, human immunodeficiency virus (hiv) infection untreated or with cd4+ t lymphocyte count <350 cells per cubic millimeter within the past 6 months, combined primary immunodeficiency disorder, taking immunosuppressive medications use of adequate contraception for females of childbearing potential