1. Has critical COVID-19 with any of the following: - Respiratory failure defined based on resource utilization requiring at least one of the following: Endotracheal intubation and mechanical ventilation, oxygen delivered by high-flow nasal cannula (heated, humidified, oxygen delivered via reinforced nasal cannula at flow rates >20 L/min with fraction of delivered oxygen ≥0.5), noninvasive positive pressure ventilation, ECMO, or clinical diagnosis of respiratory failure (i.e., clinical need for one of the preceding therapies, but preceding therapies not able to be administered in setting of resource limitation) - Shock (defined by systolic blood pressure <90 mm Hg, or diastolic blood pressure <60 mm Hg or requiring vasopressors) - Multi-organ dysfunction/failure 2. Is on dialysis or has reduced eGFR <30 mL/min/1.73m2 by the MDRD equation 3. Has any of the following conditions: - HIV with a recent viral load >50 copies/mL or CD4 <200 cell/mm³ - Chemotherapy required within 6 weeks before randomization - A neutrophilic granulocyte absolute count <500/mm3 - Autologous or allogeneic hematopoietic stem cell transplant recipient 4. Has a history of HBV or HCV infection with any of the following: - Cirrhosis - End-stage liver disease - Hepatocellular carcinoma - AST and/or ALT > 3X upper limit of normal at screening 5. Has a platelet count <100,000/μL or received a platelet transfusion in the 5 days prior to randomization. 6. Has a history of acute pancreatitis within 3 months prior to randomization or a history of chronic pancreatitis. 7. Has a baseline heart rate of < 50 beats per minute at rest. 8. Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator. 9. Has any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments including but not limited to: - Participants who are not expected to survive longer than 48 hours after randomization,or - Participants who are expected to require mechanical ventilation within 48 hours after randomization, or - Participants with a recent history of mechanical ventilation, or - Participants with conditions that could limit gastrointestinal absorption of capsule contents. 10. Is taking or is anticipated to require any prohibited therapies as outlined in the Protocol. 11. Is unwilling to abstain from participating in another interventional clinical trial through Day 29 with an investigational compound or device, including those for COVID-19 therapeutics. 12. Is anticipated to require transfer to a non-study hospital within 72 hours. 13. Is or has an immediate family member (eg, spouse, parent/legal guardian, sibling, or child) who is investigational site or Sponsor staff directly involved with this study.

1. Has critical COVID-19 with any of the following: - Respiratory failure defined based on resource utilization requiring at least one of the following: Endotracheal intubation and mechanical ventilation, oxygen delivered by high-flow nasal cannula (heated, humidified, oxygen delivered via reinforced nasal cannula at flow rates >20 L/min with fraction of delivered oxygen ≥0.5), noninvasive positive pressure ventilation, ECMO, or clinical diagnosis of respiratory failure (i.e., clinical need for one of the preceding therapies, but preceding therapies not able to be administered in setting of resource limitation) - Shock (defined by systolic blood pressure <90 mm Hg, or diastolic blood pressure <60 mm Hg or requiring vasopressors) - Multi-organ dysfunction/failure 2. Is on dialysis or has reduced eGFR <30 mL/min/1.73m2 by the MDRD equation 3. Has any of the following conditions: - HIV with a recent viral load >50 copies/mL or CD4 <200 cell/mm³ - Chemotherapy required within 6 weeks before randomization - A neutrophilic granulocyte absolute count <500/mm3 - Autologous or allogeneic hematopoietic stem cell transplant recipient 4. Has a history of HBV or HCV infection with any of the following: - Cirrhosis - End-stage liver disease - Hepatocellular carcinoma - AST and/or ALT > 3X upper limit of normal at screening 5. Has a platelet count <100,000/μL or received a platelet transfusion in the 5 days prior to randomization. 6. Has a history of acute pancreatitis within 3 months prior to randomization or a history of chronic pancreatitis. 7. Has a baseline heart rate of < 50 beats per minute at rest. 8. Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator. 9. Has any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments including but not limited to: - Participants who are not expected to survive longer than 48 hours after randomization,or - Participants who are expected to require mechanical ventilation within 48 hours after randomization, or - Participants with a recent history of mechanical ventilation, or - Participants with conditions that could limit gastrointestinal absorption of capsule contents. 10. Is taking or is anticipated to require any prohibited therapies as outlined in the Protocol. 11. Is unwilling to abstain from participating in another interventional clinical trial through Day 29 with an investigational compound or device, including those for COVID-19 therapeutics. 12. Is anticipated to require transfer to a non-study hospital within 72 hours. 13. Is or has an immediate family member (eg, spouse, parent/legal guardian, sibling, or child) who is investigational site or Sponsor staff directly involved with this study.

1. Has critical COVID-19 with any of the following: - Respiratory failure defined based on resource utilization requiring at least one of the following: Endotracheal intubation and mechanical ventilation, oxygen delivered by high-flow nasal cannula (heated, humidified, oxygen delivered via reinforced nasal cannula at flow rates >20 L/min with fraction of delivered oxygen ≥0.5), noninvasive positive pressure ventilation, ECMO, or clinical diagnosis of respiratory failure (i.e., clinical need for one of the preceding therapies, but preceding therapies not able to be administered in setting of resource limitation) - Shock (defined by systolic blood pressure <90 mm Hg, or diastolic blood pressure <60 mm Hg or requiring vasopressors) - Multi-organ dysfunction/failure 2. Is on dialysis or has reduced eGFR <30 mL/min/1.73m2 by the MDRD equation 3. Has any of the following conditions: - HIV with a recent viral load >50 copies/mL or CD4 <200 cell/mm³ - chemotherapy required within 6 weeks before randomization - a neutrophilic granulocyte absolute count <500/mm3 - autologous or allogeneic hematopoietic stem cell transplant recipient 4. Has an active diagnosis of hepatitis due to any cause, including active HBV infection (defined as HBsAg-positive) or HCV infection (defined as detectable HCV RNA). 5. Has a platelet count <100,000/μL or received a platelet transfusion in the 5 days prior to randomization. 6. Has a history of acute pancreatitis within 3 months prior to randomization or a history of chronic pancreatitis. 7. Has a baseline heart rate of < 50 beats per minute at rest. 8. Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator. 9. Has any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments including but not limited to: - Participants who are not expected to survive longer than 48 hours after randomization, - Participants who are expected to require mechanical ventilation within 48 hours after randomization, or - Participants with a recent history of mechanical ventilation not associated with COVID-19, or - Participants with conditions that could limit gastrointestinal absorption of capsule contents. 10. Is taking or is anticipated to require any prohibited therapies as outlined in the Protocol. 11. Is unwilling to abstain from participating in another interventional clinical trial through Day 29 with an investigational compound or device, including those for COVID-19 therapeutics. 12. Is anticipated to require transfer to a non-study hospital within 72 hours. 13. Is or has an immediate family member (eg, spouse, parent/legal guardian, sibling, or child) who is investigational site or Sponsor staff directly involved with this study.

1. Has critical COVID-19 with any of the following: - Respiratory failure defined based on resource utilization requiring at least one of the following: Endotracheal intubation and mechanical ventilation, oxygen delivered by high-flow nasal cannula (heated, humidified, oxygen delivered via reinforced nasal cannula at flow rates >20 L/min with fraction of delivered oxygen ≥0.5), noninvasive positive pressure ventilation, ECMO, or clinical diagnosis of respiratory failure (i.e., clinical need for one of the preceding therapies, but preceding therapies not able to be administered in setting of resource limitation) - Shock (defined by systolic blood pressure <90 mm Hg, or diastolic blood pressure <60 mm Hg or requiring vasopressors) - Multi-organ dysfunction/failure 2. Is on dialysis or has reduced eGFR <30 mL/min/1.73m2 by the MDRD equation 3. Has any of the following conditions: - HIV with a recent viral load >50 copies/mL or CD4 <200 cell/mm³ - chemotherapy required within 6 weeks before randomization - a neutrophilic granulocyte absolute count <500/mm3 - autologous or allogeneic hematopoietic stem cell transplant recipient 4. Has an active diagnosis of hepatitis due to any cause, including active HBV infection (defined as HBsAg-positive) or HCV infection (defined as detectable HCV RNA). 5. Has a platelet count <100,000/μL or received a platelet transfusion in the 5 days prior to randomization. 6. Has a history of acute pancreatitis within 3 months prior to randomization or a history of chronic pancreatitis. 7. Has a baseline heart rate of < 50 beats per minute at rest. 8. Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator. 9. Has any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments including but not limited to: - Participants who are not expected to survive longer than 48 hours after randomization, - Participants who are expected to require mechanical ventilation within 48 hours after randomization, or - Participants with a recent history of mechanical ventilation not associated with COVID-19, or - Participants with conditions that could limit gastrointestinal absorption of capsule contents. 10. Is taking or is anticipated to require any prohibited therapies as outlined in the Protocol. 11. Is unwilling to abstain from participating in another interventional clinical trial through Day 29 with an investigational compound or device, including those for COVID-19 therapeutics. 12. Is anticipated to require transfer to a non-study hospital within 72 hours. 13. Is or has an immediate family member (eg, spouse, parent/legal guardian, sibling, or child) who is investigational site or Sponsor staff directly involved with this study.