1. pregnancy (pregnant women may apply for open label treatment under compassionate care ind 2. age \<18 years 3. mechanical ventilation for more than 7 days in primary cohort. mechanical ventilation\>21 days in the exploratory cohort 4. mean arterial pressure \< 65 mm hg with use of pressor per icu protocol 5. irreversible condition (other than covid-19) with projected fatal course 6. ecmo 7. current or recent (within 30 d) enrollment in another investigational trial of anti-il6 drug; 8. active diagnosis of acquired immune deficiency syndrome; 9. transplant patients currently immunosuppressed; 10. chemotherapy-induced neutropenia (granulocyte count \<1000/mm3); 11. cardiogenic shock; congestive heart failure - nyha class 3 or 4; 12. recent myocardial infarction - within last 6 months and troponin \> 0.5 13. anuria (urine output \< 50 ml/d) or other signs of multi-organ failure 14. severe liver disease with portal hypertension; 15. recent stroke or head trauma within last 12 months 16. increased intracranial pressure, or other serious neurologic disorder; 17. liquid diarrhea more than 3x/day; defined as more than 3 non-bloody watery stools within a 24-hour period, requiring additional fluid and electrolyte supplementation

1. pregnancy (pregnant women may apply for open label treatment under compassionate care ind 2. age \<18 years 3. mechanical ventilation for more than 7 days in primary cohort. mechanical ventilation\>21 days in the exploratory cohort 4. mean arterial pressure \< 65 mm hg with use of pressor per icu protocol 5. irreversible condition (other than covid-19) with projected fatal course 6. ecmo 7. current or recent (within 30 d) enrollment in another investigational trial of anti-il6 drug; 8. active diagnosis of acquired immune deficiency syndrome; 9. transplant patients currently immunosuppressed; 10. chemotherapy-induced neutropenia (granulocyte count \<1000/mm3); 11. cardiogenic shock; congestive heart failure - nyha class 3 or 4; 12. recent myocardial infarction - within last 6 months and troponin \> 0.5 13. anuria (urine output \< 50 ml/d) or other signs of multi-organ failure 14. severe liver disease with portal hypertension; 15. recent stroke or head trauma within last 12 months 16. increased intracranial pressure, or other serious neurologic disorder; 17. liquid diarrhea more than 3x/day; defined as more than 3 non-bloody watery stools within a 24-hour period, requiring additional fluid and electrolyte supplementation

pregnancy (pregnant women may apply for open label treatment under compassionate care ind age <18 years mechanical ventilation for more than 7 days in primary cohort. mechanical ventilation>21 days in the exploratory cohort mean arterial pressure < 65 mm hg with use of pressor per icu protocol irreversible condition (other than covid-19) with projected fatal course ecmo current or recent (within 30 d) enrollment in another investigational trial of anti-il6 drug; active diagnosis of acquired immune deficiency syndrome; transplant patients currently immunosuppressed; chemotherapy-induced neutropenia (granulocyte count <1000/mm3); cardiogenic shock; congestive heart failure - nyha class 3 or 4; recent myocardial infarction - within last 6 months and troponin > 0.5 anuria (urine output < 50 ml/d) or other signs of multi-organ failure severe liver disease with portal hypertension; recent stroke or head trauma within last 12 months increased intracranial pressure, or other serious neurologic disorder; liquid diarrhea more than 3x/day; defined as more than 3 non-bloody watery stools within a 24-hour period, requiring additional fluid and electrolyte supplementation

pregnancy (pregnant women may apply for open label treatment under compassionate care ind age <18 years mechanical ventilation for more than 7 days in primary cohort. mechanical ventilation>21 days in the exploratory cohort mean arterial pressure < 65 mm hg with use of pressor per icu protocol irreversible condition (other than covid-19) with projected fatal course ecmo current or recent (within 30 d) enrollment in another investigational trial of anti-il6 drug; active diagnosis of acquired immune deficiency syndrome; transplant patients currently immunosuppressed; chemotherapy-induced neutropenia (granulocyte count <1000/mm3); cardiogenic shock; congestive heart failure - nyha class 3 or 4; recent myocardial infarction - within last 6 months and troponin > 0.5 anuria (urine output < 50 ml/d) or other signs of multi-organ failure severe liver disease with portal hypertension; recent stroke or head trauma within last 12 months increased intracranial pressure, or other serious neurologic disorder; liquid diarrhea more than 3x/day; defined as more than 3 non-bloody watery stools within a 24-hour period, requiring additional fluid and electrolyte supplementation

1. pregnancy (pregnant women may apply for open label treatment under compassionate care ind 2. age <18 years 3. mechanical ventilation for more than 7 days in primary cohort. mechanical ventilation>21 days in the exploratory cohort 4. mean arterial pressure < 65 mm hg with use of pressor per icu protocol 5. irreversible condition (other than covid-19) with projected fatal course 6. ecmo 7. current or recent (within 30 d) enrollment in another investigational trial of anti-il6 drug; 8. active diagnosis of acquired immune deficiency syndrome; 9. transplant patients currently immunosuppressed; 10. chemotherapy-induced neutropenia (granulocyte count <1000/mm3); 11. cardiogenic shock; congestive heart failure - nyha class 3 or 4; 12. recent myocardial infarction - within last 6 months and troponin > 0.5 13. anuria (urine output < 50 ml/d) or other signs of multi-organ failure 14. severe liver disease with portal hypertension; 15. recent stroke or head trauma within last 12 months 16. increased intracranial pressure, or other serious neurologic disorder; 17. liquid diarrhea more than 3x/day; defined as more than 3 non-bloody watery stools within a 24-hour period, requiring additional fluid and electrolyte supplementation

1. pregnancy (pregnant women may apply for open label treatment under compassionate care ind 2. age <18 years 3. mechanical ventilation for more than 7 days in primary cohort. mechanical ventilation>21 days in the exploratory cohort 4. mean arterial pressure < 65 mm hg with use of pressor per icu protocol 5. irreversible condition (other than covid-19) with projected fatal course 6. ecmo 7. current or recent (within 30 d) enrollment in another investigational trial of anti-il6 drug; 8. active diagnosis of acquired immune deficiency syndrome; 9. transplant patients currently immunosuppressed; 10. chemotherapy-induced neutropenia (granulocyte count <1000/mm3); 11. cardiogenic shock; congestive heart failure - nyha class 3 or 4; 12. recent myocardial infarction - within last 6 months and troponin > 0.5 13. anuria (urine output < 50 ml/d) or other signs of multi-organ failure 14. severe liver disease with portal hypertension; 15. recent stroke or head trauma within last 12 months 16. increased intracranial pressure, or other serious neurologic disorder; 17. liquid diarrhea more than 3x/day; defined as more than 3 non-bloody watery stools within a 24-hour period, requiring additional fluid and electrolyte supplementation