requiring hospitalization at time of screening, or at time of study drug administration. oxygen saturation (spo2) ≤ 93% on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in mmhg) to fractional inspired oxygen (fio2) < 300, respiratory rate ≥ 30 per minute, and heart rate ≥ 125 per minute. known allergies to any of the components used in the formulation of the ensovibep or placebo. suspected or proven serious, active bacterial, fungal, viral, or other infection (besides sars-cov-2) that in the opinion of the investigator could constitute a risk when taking intervention. any serious concomitant systemic disease, condition, or disorder that, in the opinion of the investigator, should preclude participation in this study. any co-morbidity requiring surgery within 7 days of dosing, or that is considered life-threatening within 29 days of dosing. prior or concurrent use of any medication for treatment of covid-19, including antiviral agents, convalescent serum, or anti-viral antibodies. purely symptomatic therapies (e.g., over-the-counter [otc] cough medications, acetaminophen, and nonsteroidal anti-inflammatories [nsaids]) are permitted. prior use of steroids for management of covid-19 symptoms may be permitted, provided they can be stopped at study entry based on investigator judgement.prior vaccination for covid-19 is permitted. part b inclusion criteria: males or females ≥ 12 years of age on the day of inclusion (no upper limit) and with a body weight of ≥ 40kg presence of two or more of the following covid-19 symptoms with an onset within 7 days of dosing: feeling hot or feverish, cough, sore throat, low energy or tiredness, headache, muscle or body aches, chills or shivering, and shortness of breath positive test for sars-cov-2 in upper respiratory swab within 24 hours prior to dosing (rapid antigen test) presence of at least one of the following medical conditions or factors that places patients at higher risk for progression to severe covid-19. age ≥ 60 years obesity [body mass index (bmi) ≥30 kg/m2, or if age 12-17 years, have bmi ≥95th percentile for their age and gender based on cdc growth charts] chronic kidney disease diabetes hypertension immunosuppressive disease or immunosuppressive treatment cardiovascular disease (including congenital heart disease) chronic lung diseases cancer sickle cell disease neurodevelopmental disorders other medical conditions that confer medical complexity (for example, genetic or metabolic syndromes and severe congenital anomalies) having a medical-related technological dependence [for example, tracheostomy, gastrostomy, or positive pressure ventilation (not related to covid-19)] the patient or legally authorized representative understands and agrees to comply with the planned study procedures. the patient, legally authorized representative, or parent/legal guardian gives signed informed consent and adolescents provide assent. part b

requiring hospitalization at time of screening, or at time of study drug administration. oxygen saturation (spo2) ≤ 93% on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in mmhg) to fractional inspired oxygen (fio2) < 300, respiratory rate ≥ 30 per minute, and heart rate ≥ 125 per minute. known allergies to any of the components used in the formulation of the ensovibep or placebo. suspected or proven serious, active bacterial, fungal, viral, or other infection (besides sars-cov-2) that in the opinion of the investigator could constitute a risk when taking intervention. any serious concomitant systemic disease, condition, or disorder that, in the opinion of the investigator, should preclude participation in this study. any co-morbidity requiring surgery within 7 days of dosing, or that is considered life-threatening within 29 days of dosing. prior or concurrent use of any medication for treatment of covid-19, including antiviral agents, convalescent serum, or anti-viral antibodies. purely symptomatic therapies (e.g., over-the-counter [otc] cough medications, acetaminophen, and nonsteroidal anti-inflammatories [nsaids]) are permitted. prior use of steroids for management of covid-19 symptoms may be permitted, provided they can be stopped at study entry based on investigator judgement.prior vaccination for covid-19 is permitted. part b inclusion criteria: males or females ≥ 12 years of age on the day of inclusion (no upper limit) and with a body weight of ≥ 40kg presence of two or more of the following covid-19 symptoms with an onset within 7 days of dosing: feeling hot or feverish, cough, sore throat, low energy or tiredness, headache, muscle or body aches, chills or shivering, and shortness of breath positive test for sars-cov-2 in upper respiratory swab within 24 hours prior to dosing (rapid antigen test) presence of at least one of the following medical conditions or factors that places patients at higher risk for progression to severe covid-19. age ≥ 60 years obesity [body mass index (bmi) ≥30 kg/m2, or if age 12-17 years, have bmi ≥95th percentile for their age and gender based on cdc growth charts] chronic kidney disease diabetes hypertension immunosuppressive disease or immunosuppressive treatment cardiovascular disease (including congenital heart disease) chronic lung diseases cancer sickle cell disease neurodevelopmental disorders other medical conditions that confer medical complexity (for example, genetic or metabolic syndromes and severe congenital anomalies) having a medical-related technological dependence [for example, tracheostomy, gastrostomy, or positive pressure ventilation (not related to covid-19)] the patient or legally authorized representative understands and agrees to comply with the planned study procedures. the patient, legally authorized representative, or parent/legal guardian gives signed informed consent and adolescents provide assent. part b

requiring hospitalization at time of screening, or at time of study drug administration. oxygen saturation (spo2) ≤ 93% on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in mmhg) to fractional inspired oxygen (fio2) < 300, respiratory rate ≥ 30 per minute, and heart rate ≥ 125 per minute. known allergies to any of the components used in the formulation of the ensovibep or placebo. suspected or proven serious, active bacterial, fungal, viral, or other infection (besides sars-cov-2) that in the opinion of the investigator could constitute a risk when taking intervention. any serious concomitant systemic disease, condition, or disorder that, in the opinion of the investigator, should preclude participation in this study. any co-morbidity requiring surgery within 7 days of dosing, or that is considered life-threatening within 29 days of dosing. prior or concurrent use of any medication for treatment of covid-19, including antiviral agents, convalescent serum, or anti-viral antibodies. purely symptomatic therapies (e.g., over-the-counter [otc] cough medications, acetaminophen, and nonsteroidal anti-inflammatories [nsaids]) are permitted. prior vaccination for covid-19 is permitted.

requiring hospitalization at time of screening, or at time of study drug administration. oxygen saturation (spo2) ≤ 93% on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in mmhg) to fractional inspired oxygen (fio2) < 300, respiratory rate ≥ 30 per minute, and heart rate ≥ 125 per minute. known allergies to any of the components used in the formulation of the ensovibep or placebo. suspected or proven serious, active bacterial, fungal, viral, or other infection (besides sars-cov-2) that in the opinion of the investigator could constitute a risk when taking intervention. any serious concomitant systemic disease, condition, or disorder that, in the opinion of the investigator, should preclude participation in this study. any co-morbidity requiring surgery within 7 days of dosing, or that is considered life-threatening within 29 days of dosing. prior or concurrent use of any medication for treatment of covid-19, including antiviral agents, convalescent serum, or anti-viral antibodies. purely symptomatic therapies (e.g., over-the-counter [otc] cough medications, acetaminophen, and nonsteroidal anti-inflammatories [nsaids]) are permitted. prior vaccination for covid-19 is permitted.

1. requiring hospitalization at time of screening, or at time of study drug administration. 2. oxygen saturation (spo2) ≤ 93% on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in mmhg) to fractional inspired oxygen (fio2) < 300, respiratory rate ≥ 30 per minute, and heart rate ≥ 125 per minute. 3. known allergies to any of the components used in the formulation of the ensovibep or placebo. 4. suspected or proven serious, active bacterial, fungal, viral, or other infection (besides sars-cov-2) that in the opinion of the investigator could constitute a risk when taking intervention. 5. any serious concomitant systemic disease, condition, or disorder that, in the opinion of the investigator, should preclude participation in this study. 6. any co-morbidity requiring surgery within 7 days of dosing, or that is considered life-threatening within 29 days of dosing. 7. prior or concurrent use of any medication for treatment of covid-19, including antiviral agents, convalescent serum, or anti-viral antibodies. purely symptomatic therapies (e.g., over-the-counter [otc] cough medications, acetaminophen, and nonsteroidal anti-inflammatories [nsaids]) are permitted. prior vaccination for covid-19 is permitted.

1. requiring hospitalization at time of screening, or at time of study drug administration. 2. oxygen saturation (spo2) ≤ 93% on room air at sea level or ratio of arterial oxygen partial pressure (pao2 in mmhg) to fractional inspired oxygen (fio2) < 300, respiratory rate ≥ 30 per minute, and heart rate ≥ 125 per minute. 3. known allergies to any of the components used in the formulation of the ensovibep or placebo. 4. suspected or proven serious, active bacterial, fungal, viral, or other infection (besides sars-cov-2) that in the opinion of the investigator could constitute a risk when taking intervention. 5. any serious concomitant systemic disease, condition, or disorder that, in the opinion of the investigator, should preclude participation in this study. 6. any co-morbidity requiring surgery within 7 days of dosing, or that is considered life-threatening within 29 days of dosing. 7. prior or concurrent use of any medication for treatment of covid-19, including antiviral agents, convalescent serum, or anti-viral antibodies. purely symptomatic therapies (e.g., over-the-counter [otc] cough medications, acetaminophen, and nonsteroidal anti-inflammatories [nsaids]) are permitted. prior vaccination for covid-19 is permitted.