1. Not receiving invasive mechanical ventilation or non invasive ventilation 2. More than 96 hours from the onset of ARDS 3. Age < 18 years 4. Known to be pregnant or breastfeeding 5. Participation in a clinical trial of interferon therapies, immune plasma therapies or immunoglobulin within 30 days 6. Major trauma in the prior 5 days 7. Presence of any active malignancy (other than non-melanoma skin cancer) that required treatment within the last year 8. WHO Class III or IV pulmonary hypertension 9. Pulmonary embolism within past 3 months 10. Currently receiving extracorporeal life support (ECLS) 11. Currently receiving renal replacement therapy 12. Severe chronic liver disease with Child-Pugh score > 12 13. DNAR (Do Not Attempt Resuscitation) order in place 14. Treatment withdrawal imminent within 24 hours 15. Prisoners 16. Non-English speaking patients or those who do not adequately understand verbal or written information unless an interpreter is available. 17. Enrolled in a concomitant clinical trial of interferon therapies, immune plasma therapies or immunoglobulin. 18. IgA deficiency

1. Not receiving invasive mechanical ventilation or non invasive ventilation 2. More than 96 hours from the onset of ARDS 3. Age < 18 years 4. Known to be pregnant or breastfeeding 5. Participation in a clinical trial of interferon therapies, immune plasma therapies or immunoglobulin within 30 days 6. Major trauma in the prior 5 days 7. Presence of any active malignancy (other than non-melanoma skin cancer) that required treatment within the last year 8. WHO Class III or IV pulmonary hypertension 9. Pulmonary embolism within past 3 months 10. Currently receiving extracorporeal life support (ECLS) 11. Currently receiving renal replacement therapy 12. Severe chronic liver disease with Child-Pugh score > 12 13. DNAR (Do Not Attempt Resuscitation) order in place 14. Treatment withdrawal imminent within 24 hours 15. Prisoners 16. Non-English speaking patients or those who do not adequately understand verbal or written information unless an interpreter is available. 17. Enrolled in a concomitant clinical trial of interferon therapies, immune plasma therapies or immunoglobulin. 18. IgA deficiency

1. Not receiving invasive mechanical ventilation 2. More than 96 hours from the onset of ARDS 3. Age < 18 years 4. Known to be pregnant or breastfeeding 5. Participation in a clinical trial of an investigational medicinal product (other than antibiotics or anti-virals) within 30 days 6. Major trauma in the prior 5 days 7. Presence of any active malignancy (other than non-melanoma skin cancer) that required treatment within the last year 8. WHO Class III or IV pulmonary hypertension 9. Pulmonary embolism within past 3 months 10. Currently receiving extracorporeal life support (ECLS) 11. Currently receiving renal replacement therapy 12. Severe chronic liver disease with Child-Pugh score > 12 13. DNAR (Do Not Attempt Resuscitation) order in place 14. Treatment withdrawal imminent within 24 hours 15. Prisoners 16. Non-English speaking patients or those who do not adequately understand verbal or written information unless an interpreter is available. 17. Enrolled in a concomitant clinical trial of a medicinal product (other than antibiotic or anti-virals) 18. IgA deficiency

1. Not receiving invasive mechanical ventilation 2. More than 96 hours from the onset of ARDS 3. Age < 18 years 4. Known to be pregnant or breastfeeding 5. Participation in a clinical trial of an investigational medicinal product (other than antibiotics or anti-virals) within 30 days 6. Major trauma in the prior 5 days 7. Presence of any active malignancy (other than non-melanoma skin cancer) that required treatment within the last year 8. WHO Class III or IV pulmonary hypertension 9. Pulmonary embolism within past 3 months 10. Currently receiving extracorporeal life support (ECLS) 11. Currently receiving renal replacement therapy 12. Severe chronic liver disease with Child-Pugh score > 12 13. DNAR (Do Not Attempt Resuscitation) order in place 14. Treatment withdrawal imminent within 24 hours 15. Prisoners 16. Non-English speaking patients or those who do not adequately understand verbal or written information unless an interpreter is available. 17. Enrolled in a concomitant clinical trial of a medicinal product (other than antibiotic or anti-virals) 18. IgA deficiency