* for low-risk participants only: bmi ≥35 * have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) \<300, respiratory rate ≥30 per minute, heart rate ≥125 per minute * require mechanical ventilation or anticipated impending need for mechanical ventilation * have known allergies to any of the components used in the formulation of the interventions * have hemodynamic instability requiring use of pressors within 24 hours of randomization * suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention * have any co-morbidity requiring surgery within \<7 days, or that is considered life-threatening within 29 days * have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study * have a history of a positive severe acute respiratory syndrome coronavirus 2 (sars-cov-2) test prior to the one serving as eligibility for this study * have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing * have received treatment with a sars-cov-2 specific monoclonal antibody * have a history of convalescent covid-19 plasma treatment * for low-risk arms only: have received a sars-cov-2 vaccine or have participated in a previous sars-cov-2 vaccine study and are currently blinded to treatment allotment * have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed * are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study * are pregnant or breast feeding * are investigator site personnel directly affiliated with this study * have body weight \<40 kilograms

* for low-risk participants only: bmi ≥35 * have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) \<300, respiratory rate ≥30 per minute, heart rate ≥125 per minute * require mechanical ventilation or anticipated impending need for mechanical ventilation * have known allergies to any of the components used in the formulation of the interventions * have hemodynamic instability requiring use of pressors within 24 hours of randomization * suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention * have any co-morbidity requiring surgery within \<7 days, or that is considered life-threatening within 29 days * have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study * have a history of a positive severe acute respiratory syndrome coronavirus 2 (sars-cov-2) test prior to the one serving as eligibility for this study * have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing * have received treatment with a sars-cov-2 specific monoclonal antibody * have a history of convalescent covid-19 plasma treatment * for low-risk arms only: have received a sars-cov-2 vaccine or have participated in a previous sars-cov-2 vaccine study and are currently blinded to treatment allotment * have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed * are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study * are pregnant or breast feeding * are investigator site personnel directly affiliated with this study * have body weight \<40 kilograms

for low-risk participants only: bmi ≥35 have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) <300, respiratory rate ≥30 per minute, heart rate ≥125 per minute require mechanical ventilation or anticipated impending need for mechanical ventilation have known allergies to any of the components used in the formulation of the interventions have hemodynamic instability requiring use of pressors within 24 hours of randomization suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study have a history of a positive severe acute respiratory syndrome coronavirus 2 (sars-cov-2) test prior to the one serving as eligibility for this study have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing have received treatment with a sars-cov-2 specific monoclonal antibody have a history of convalescent covid-19 plasma treatment for low-risk arms only: have received a sars-cov-2 vaccine or have participated in a previous sars-cov-2 vaccine study and are currently blinded to treatment allotment have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study are pregnant or breast feeding are investigator site personnel directly affiliated with this study have body weight <40 kilograms

for low-risk participants only: bmi ≥35 have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) <300, respiratory rate ≥30 per minute, heart rate ≥125 per minute require mechanical ventilation or anticipated impending need for mechanical ventilation have known allergies to any of the components used in the formulation of the interventions have hemodynamic instability requiring use of pressors within 24 hours of randomization suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study have a history of a positive severe acute respiratory syndrome coronavirus 2 (sars-cov-2) test prior to the one serving as eligibility for this study have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing have received treatment with a sars-cov-2 specific monoclonal antibody have a history of convalescent covid-19 plasma treatment for low-risk arms only: have received a sars-cov-2 vaccine or have participated in a previous sars-cov-2 vaccine study and are currently blinded to treatment allotment have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study are pregnant or breast feeding are investigator site personnel directly affiliated with this study have body weight <40 kilograms

- for low-risk participants only: bmi ≥35 - have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) <300, respiratory rate ≥30 per minute, heart rate ≥125 per minute - require mechanical ventilation or anticipated impending need for mechanical ventilation - have known allergies to any of the components used in the formulation of the interventions - have hemodynamic instability requiring use of pressors within 24 hours of randomization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention - have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days - have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study - have a history of a positive sars-cov-2 test prior to the one serving as eligibility for this study - have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing - have received treatment with a sars-cov-2 specific monoclonal antibody - have a history of convalescent covid-19 plasma treatment - for low-risk arms only: have received a sars-cov-2 vaccine or have participated in a previous sars-cov-2 vaccine study and are currently blinded to treatment allotment - have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed - are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study - are pregnant or breast feeding - are investigator site personnel directly affiliated with this study - have body weight <40 kilograms

- for low-risk participants only: bmi ≥35 - have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) <300, respiratory rate ≥30 per minute, heart rate ≥125 per minute - require mechanical ventilation or anticipated impending need for mechanical ventilation - have known allergies to any of the components used in the formulation of the interventions - have hemodynamic instability requiring use of pressors within 24 hours of randomization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention - have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days - have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study - have a history of a positive sars-cov-2 test prior to the one serving as eligibility for this study - have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing - have received treatment with a sars-cov-2 specific monoclonal antibody - have a history of convalescent covid-19 plasma treatment - for low-risk arms only: have received a sars-cov-2 vaccine or have participated in a previous sars-cov-2 vaccine study and are currently blinded to treatment allotment - have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed - are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study - are pregnant or breast feeding - are investigator site personnel directly affiliated with this study - have body weight <40 kilograms

- for low-risk participants only: bmi ≥35 - have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) <300, respiratory rate ≥30 per minute, heart rate ≥125 per minute - require mechanical ventilation or anticipated impending need for mechanical ventilation - have known allergies to any of the components used in the formulation of the interventions - have hemodynamic instability requiring use of pressors within 24 hours of randomization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention - have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days - have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study - have a history of a positive sars-cov-2 test prior to the one serving as eligibility for this study - have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing - have received treatment with a sars-cov-2 specific monoclonal antibody - have a history of convalescent covid-19 plasma treatment - for low-risk arms only: have participated in a previous sars-cov-2 vaccine study or have received a sars-cov-2 vaccine - have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed - are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study - are pregnant or breast feeding - are investigator site personnel directly affiliated with this study - have body weight <40 kilograms

- for low-risk participants only: bmi ≥35 - have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) <300, respiratory rate ≥30 per minute, heart rate ≥125 per minute - require mechanical ventilation or anticipated impending need for mechanical ventilation - have known allergies to any of the components used in the formulation of the interventions - have hemodynamic instability requiring use of pressors within 24 hours of randomization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention - have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days - have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study - have a history of a positive sars-cov-2 test prior to the one serving as eligibility for this study - have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing - have received treatment with a sars-cov-2 specific monoclonal antibody - have a history of convalescent covid-19 plasma treatment - for low-risk arms only: have participated in a previous sars-cov-2 vaccine study or have received a sars-cov-2 vaccine - have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed - are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study - are pregnant or breast feeding - are investigator site personnel directly affiliated with this study - have body weight <40 kilograms

- body mass index (bmi) greater than or equal to (≥)35 - have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) less than (<)300, respiratory rate ≥30 per minute, heart rate ≥125 per minute - require mechanical ventilation or anticipated impending need for mechanical ventilation - have known allergies to any of the components used in the formulation of the interventions - have hemodynamic instability requiring use of pressors within 24 hours of randomization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention - have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days - have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study - have a history of a positive sars-cov-2 test prior to the one serving as eligibility for this study - have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing - have received treatment with a sars-cov-2 specific monoclonal antibody - have a history of convalescent covid-19 plasma treatment - have participated in a previous sars-cov-2 vaccine study or have received a sars-cov-2 vaccine - have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed - are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study - are pregnant or breast feeding - are investigator site personnel directly affiliated with this study

- body mass index (bmi) greater than or equal to (≥)35 - have oxygen saturation (spo2) less than or equal to (≤)93 percent (%) on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in millimeters of mercury) to fractional inspired oxygen (fio2) less than (<)300, respiratory rate ≥30 per minute, heart rate ≥125 per minute - require mechanical ventilation or anticipated impending need for mechanical ventilation - have known allergies to any of the components used in the formulation of the interventions - have hemodynamic instability requiring use of pressors within 24 hours of randomization - suspected or proven serious, active bacterial, fungal, viral, or other infection (besides covid-19) that in the opinion of the investigator could constitute a risk when taking intervention - have any co-morbidity requiring surgery within <7 days, or that is considered life-threatening within 29 days - have any serious concomitant systemic disease, condition or disorder that, in the opinion of the investigator, should preclude participation in this study - have a history of a positive sars-cov-2 test prior to the one serving as eligibility for this study - have received an investigational intervention for sars-cov-2 prophylaxis within 30 days before dosing - have received treatment with a sars-cov-2 specific monoclonal antibody - have a history of convalescent covid-19 plasma treatment - have participated in a previous sars-cov-2 vaccine study or have received a sars-cov-2 vaccine - have participated, within the last 30 days, in a clinical study involving an investigational intervention. if the previous investigational intervention has a long half-life, 5 half-lives or 30 days, whichever is longer, should have passed - are concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study - are pregnant or breast feeding - are investigator site personnel directly affiliated with this study