key inclusion criteria: * willing and able to provide written informed consent, (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and \< 18 years of age) prior to performing study procedures. individuals age ≥ 18 years may be enrolled with the consent of a legal representative where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec). for individuals ≥ 12 and \< 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures * either: * age ≥ 18 years (at all sites) or aged ≥ 12 and \< 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant irb or iec with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) * or aged ≥ 60 years * severe acute respiratory syndrome (sars)-coronavirus (cov)-2 infection confirmed by molecular diagnosis (nucleic acid (polymerase chain reaction (pcr) or antigen testing) ≤ 4 days prior to screening * presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization * not currently requiring hospitalization (hospitalization defined as ≥ 24 hours of acute care) key

key inclusion criteria: * willing and able to provide written informed consent, (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and \< 18 years of age) prior to performing study procedures. individuals age ≥ 18 years may be enrolled with the consent of a legal representative where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec). for individuals ≥ 12 and \< 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures * either: * age ≥ 18 years (at all sites) or aged ≥ 12 and \< 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant irb or iec with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) * or aged ≥ 60 years * severe acute respiratory syndrome (sars)-coronavirus (cov)-2 infection confirmed by molecular diagnosis (nucleic acid (polymerase chain reaction (pcr) or antigen testing) ≤ 4 days prior to screening * presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization * not currently requiring hospitalization (hospitalization defined as ≥ 24 hours of acute care) key

key inclusion criteria: willing and able to provide written informed consent, (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and < 18 years of age) prior to performing study procedures. individuals age ≥ 18 years may be enrolled with the consent of a legal representative where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec). for individuals ≥ 12 and < 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures either: age ≥ 18 years (at all sites) or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant irb or iec with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) or aged ≥ 60 years severe acute respiratory syndrome (sars)-coronavirus (cov)-2 infection confirmed by molecular diagnosis (nucleic acid (polymerase chain reaction (pcr) or antigen testing) ≤ 4 days prior to screening presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization not currently requiring hospitalization (hospitalization defined as ≥ 24 hours of acute care) key

key inclusion criteria: willing and able to provide written informed consent, (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and < 18 years of age) prior to performing study procedures. individuals age ≥ 18 years may be enrolled with the consent of a legal representative where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec). for individuals ≥ 12 and < 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures either: age ≥ 18 years (at all sites) or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant irb or iec with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) or aged ≥ 60 years severe acute respiratory syndrome (sars)-coronavirus (cov)-2 infection confirmed by molecular diagnosis (nucleic acid (polymerase chain reaction (pcr) or antigen testing) ≤ 4 days prior to screening presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization not currently requiring hospitalization (hospitalization defined as ≥ 24 hours of acute care) key

key inclusion criteria: - willing and able to provide written informed consent, (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and < 18 years of age) prior to performing study procedures. individuals age ≥ 18 years may be enrolled with the consent of a legal representative where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec). for individuals ≥ 12 and < 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures - either: - age ≥ 18 years (at all sites) or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant irb or iec with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) - or aged ≥ 60 years - sars-cov-2 infection confirmed by molecular diagnosis (nucleic acid (polymerase chain reaction (pcr) or antigen testing) ≤ 4 days prior to screening - presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization - not currently requiring hospitalization (hospitalization defined as ≥ 24 hours of acute care) key

key inclusion criteria: - willing and able to provide written informed consent, (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and < 18 years of age) prior to performing study procedures. individuals age ≥ 18 years may be enrolled with the consent of a legal representative where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec). for individuals ≥ 12 and < 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures - either: - age ≥ 18 years (at all sites) or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant irb or iec with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) - or aged ≥ 60 years - sars-cov-2 infection confirmed by molecular diagnosis (nucleic acid (polymerase chain reaction (pcr) or antigen testing) ≤ 4 days prior to screening - presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization - not currently requiring hospitalization (hospitalization defined as ≥ 24 hours of acute care) key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and < 18 years of age) prior to performing study procedures. for individuals ≥ 12 and < 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures - either: - age ≥ 18 years (at all sites) or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec) with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) - or aged ≥ 60 years - sars-cov-2 infection confirmed by polymerase chain reaction (pcr) ≤ 4 days prior to screening - presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization - oxygen saturation (spo2) > 94% on room air - not currently requiring hospitalization key

key inclusion criteria: - willing and able to provide written informed consent, or with a legal representative who can provide informed consent (individuals ≥ 18 years of age) or assent (individuals ≥ 12 and < 18 years of age) prior to performing study procedures. for individuals ≥ 12 and < 18 years of age, a parent or legal guardian must be willing and able to provide written informed consent prior to performing study procedures - either: - age ≥ 18 years (at all sites) or aged ≥ 12 and < 18 years of age weighing ≥ 40 kg (where permitted according to local law and approved nationally and by the relevant institutional review board (irb) or independent ethics committee (iec) with at least 1 pre-existing risk factor for progression to hospitalization (chronic lung disease, hypertension, cardiovascular or cerebrovascular disease, diabetes, obesity (body mass index ≥ 30), immunocompromised, chronic mild or moderate kidney disease, chronic liver disease, current cancer, or sickle cell disease) - or aged ≥ 60 years - sars-cov-2 infection confirmed by polymerase chain reaction (pcr) ≤ 4 days prior to screening - presence of ≥ 1 symptom(s) consistent with covid-19 for ≤ 7 days prior to randomization - oxygen saturation (spo2) > 94% on room air - not currently requiring hospitalization key