1. existence of other evidence that can explain pneumonia including but not limited to: influenza a virus, influenza b virus, bacterial pneumonia (as suggested by the combined clinical picture, radiological findings and known laboratory results \[eg, elevated procalcitonin \>0.5ng/ml and concomitant neutrophilia\]), known fungal pneumonia, suspected fungal pneumonia based on compromised immune system with a history of past fungal infections, noninfectious causes, etc. 2. known history of serious allergic reactions, including anaphylaxis, to ivig or its preparation components 3. subjects with a history of thromboembolic event (tee) within the last 12 months, such as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, transient ischemic attack, peripheral artery disease (fontaine iv) 4. subjects with an underlying medical condition that can lead to hypercoagulable states and hyperviscosity such as antithrombin iii deficiency, factor v leiden, protein c deficiency, antiphospholipid syndrome and malignancy 5. known history of selective iga deficiency with antibodies against iga 6. subjects with conditions such as human immunodeficiency virus (hiv) infection, known acute or chronic hepatitis b or c (hbsag positive or hcv ribonucleic acid (rna) pcr positive or currently treated with antivirals), pulmonary fibrosis, elevated procalcitonin (\> 0.5) with concomitant neutrophilia (elevated polys), heparin induced thrombocytopenia (hit), and moderate to severe renal dysfunction (per investigator discretion based on estimated glomerular filtration rate \[egfr\] \<59 ml/min/1.73 m2, as defined by kdigo clinical practice guideline): * moderately reduced gfr (g3a): gfr = 45 to 59 ml/min/1.73 m2 * moderately reduced gfr (g3b): gfr = 30 to 44 ml/min/1.73 m2 * severely reduced gfr (g4): gfr = 15 to 29 ml/min/1.73 m2 * kidney failure (g5): gfr \<15 ml/min/1.73 m2 7. currently requiring imv (invasive mechanical ventilation or having received imv during the last 30 days 8. known clinically significant preexisting lung, heart, or neuromuscular disease that, in the investigator's opinion, would impact subject's ability to complete study or may confound the study results 9. body weight \>125 kg 10. women who are pregnant or breast-feeding 11. subjects who received covid-19 convalescent plasma, ivig products, anti-interleukin agents (eg, tocilizumab), or interferons for their covid-19 disease before enrollment or plan to receive this treatment during the course of the study 12. enrolled in other experimental interventional studies or taking experimental medications (ie, convalescent plasma). diagnostic studies can be allowed if the anticipated total blood volume to be drawn across both studies and for therapeutic purposes does not exceed 450 ml over any 8-week period.

1. existence of other evidence that can explain pneumonia including but not limited to: influenza a virus, influenza b virus, bacterial pneumonia (as suggested by the combined clinical picture, radiological findings and known laboratory results \[eg, elevated procalcitonin \>0.5ng/ml and concomitant neutrophilia\]), known fungal pneumonia, suspected fungal pneumonia based on compromised immune system with a history of past fungal infections, noninfectious causes, etc. 2. known history of serious allergic reactions, including anaphylaxis, to ivig or its preparation components 3. subjects with a history of thromboembolic event (tee) within the last 12 months, such as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, transient ischemic attack, peripheral artery disease (fontaine iv) 4. subjects with an underlying medical condition that can lead to hypercoagulable states and hyperviscosity such as antithrombin iii deficiency, factor v leiden, protein c deficiency, antiphospholipid syndrome and malignancy 5. known history of selective iga deficiency with antibodies against iga 6. subjects with conditions such as human immunodeficiency virus (hiv) infection, known acute or chronic hepatitis b or c (hbsag positive or hcv ribonucleic acid (rna) pcr positive or currently treated with antivirals), pulmonary fibrosis, elevated procalcitonin (\> 0.5) with concomitant neutrophilia (elevated polys), heparin induced thrombocytopenia (hit), and moderate to severe renal dysfunction (per investigator discretion based on estimated glomerular filtration rate \[egfr\] \<59 ml/min/1.73 m2, as defined by kdigo clinical practice guideline): * moderately reduced gfr (g3a): gfr = 45 to 59 ml/min/1.73 m2 * moderately reduced gfr (g3b): gfr = 30 to 44 ml/min/1.73 m2 * severely reduced gfr (g4): gfr = 15 to 29 ml/min/1.73 m2 * kidney failure (g5): gfr \<15 ml/min/1.73 m2 7. currently requiring imv (invasive mechanical ventilation or having received imv during the last 30 days 8. known clinically significant preexisting lung, heart, or neuromuscular disease that, in the investigator's opinion, would impact subject's ability to complete study or may confound the study results 9. body weight \>125 kg 10. women who are pregnant or breast-feeding 11. subjects who received covid-19 convalescent plasma, ivig products, anti-interleukin agents (eg, tocilizumab), or interferons for their covid-19 disease before enrollment or plan to receive this treatment during the course of the study 12. enrolled in other experimental interventional studies or taking experimental medications (ie, convalescent plasma). diagnostic studies can be allowed if the anticipated total blood volume to be drawn across both studies and for therapeutic purposes does not exceed 450 ml over any 8-week period.

existence of other evidence that can explain pneumonia including but not limited to: influenza a virus, influenza b virus, bacterial pneumonia (as suggested by the combined clinical picture, radiological findings and known laboratory results [eg, elevated procalcitonin >0.5ng/ml and concomitant neutrophilia]), known fungal pneumonia, suspected fungal pneumonia based on compromised immune system with a history of past fungal infections, noninfectious causes, etc. known history of serious allergic reactions, including anaphylaxis, to ivig or its preparation components subjects with a history of thromboembolic event (tee) within the last 12 months, such as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, transient ischemic attack, peripheral artery disease (fontaine iv) subjects with an underlying medical condition that can lead to hypercoagulable states and hyperviscosity such as antithrombin iii deficiency, factor v leiden, protein c deficiency, antiphospholipid syndrome and malignancy known history of selective iga deficiency with antibodies against iga subjects with conditions such as human immunodeficiency virus (hiv) infection, known acute or chronic hepatitis b or c (hbsag positive or hcv ribonucleic acid (rna) pcr positive or currently treated with antivirals), pulmonary fibrosis, elevated procalcitonin (> 0.5) with concomitant neutrophilia (elevated polys), heparin induced thrombocytopenia (hit), and moderate to severe renal dysfunction (per investigator discretion based on estimated glomerular filtration rate [egfr] <59 ml/min/1.73 m2, as defined by kdigo clinical practice guideline): moderately reduced gfr (g3a): gfr = 45 to 59 ml/min/1.73 m2 moderately reduced gfr (g3b): gfr = 30 to 44 ml/min/1.73 m2 severely reduced gfr (g4): gfr = 15 to 29 ml/min/1.73 m2 kidney failure (g5): gfr <15 ml/min/1.73 m2 currently requiring imv (invasive mechanical ventilation or having received imv during the last 30 days known clinically significant preexisting lung, heart, or neuromuscular disease that, in the investigator's opinion, would impact subject's ability to complete study or may confound the study results body weight >125 kg women who are pregnant or breast-feeding subjects who received covid-19 convalescent plasma, ivig products, anti-interleukin agents (eg, tocilizumab), or interferons for their covid-19 disease before enrollment or plan to receive this treatment during the course of the study enrolled in other experimental interventional studies or taking experimental medications (ie, convalescent plasma). diagnostic studies can be allowed if the anticipated total blood volume to be drawn across both studies and for therapeutic purposes does not exceed 450 ml over any 8-week period.

existence of other evidence that can explain pneumonia including but not limited to: influenza a virus, influenza b virus, bacterial pneumonia (as suggested by the combined clinical picture, radiological findings and known laboratory results [eg, elevated procalcitonin >0.5ng/ml and concomitant neutrophilia]), known fungal pneumonia, suspected fungal pneumonia based on compromised immune system with a history of past fungal infections, noninfectious causes, etc. known history of serious allergic reactions, including anaphylaxis, to ivig or its preparation components subjects with a history of thromboembolic event (tee) within the last 12 months, such as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, transient ischemic attack, peripheral artery disease (fontaine iv) subjects with an underlying medical condition that can lead to hypercoagulable states and hyperviscosity such as antithrombin iii deficiency, factor v leiden, protein c deficiency, antiphospholipid syndrome and malignancy known history of selective iga deficiency with antibodies against iga subjects with conditions such as human immunodeficiency virus (hiv) infection, known acute or chronic hepatitis b or c (hbsag positive or hcv ribonucleic acid (rna) pcr positive or currently treated with antivirals), pulmonary fibrosis, elevated procalcitonin (> 0.5) with concomitant neutrophilia (elevated polys), heparin induced thrombocytopenia (hit), and moderate to severe renal dysfunction (per investigator discretion based on estimated glomerular filtration rate [egfr] <59 ml/min/1.73 m2, as defined by kdigo clinical practice guideline): moderately reduced gfr (g3a): gfr = 45 to 59 ml/min/1.73 m2 moderately reduced gfr (g3b): gfr = 30 to 44 ml/min/1.73 m2 severely reduced gfr (g4): gfr = 15 to 29 ml/min/1.73 m2 kidney failure (g5): gfr <15 ml/min/1.73 m2 currently requiring imv (invasive mechanical ventilation or having received imv during the last 30 days known clinically significant preexisting lung, heart, or neuromuscular disease that, in the investigator's opinion, would impact subject's ability to complete study or may confound the study results body weight >125 kg women who are pregnant or breast-feeding subjects who received covid-19 convalescent plasma, ivig products, anti-interleukin agents (eg, tocilizumab), or interferons for their covid-19 disease before enrollment or plan to receive this treatment during the course of the study enrolled in other experimental interventional studies or taking experimental medications (ie, convalescent plasma). diagnostic studies can be allowed if the anticipated total blood volume to be drawn across both studies and for therapeutic purposes does not exceed 450 ml over any 8-week period.

1. existence of other evidence that can explain pneumonia including but not limited to: influenza a virus, influenza b virus, bacterial pneumonia (as suggested by the combined clinical picture, radiological findings and known laboratory results [eg, elevated procalcitonin >0.5ng/ml and concomitant neutrophilia]), known fungal pneumonia, suspected fungal pneumonia based on compromised immune system with a history of past fungal infections, noninfectious causes, etc. 2. known history of serious allergic reactions, including anaphylaxis, to ivig or its preparation components 3. subjects with a history of thromboembolic event (tee) within the last 12 months, such as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, transient ischemic attack, peripheral artery disease (fontaine iv) 4. subjects with an underlying medical condition that can lead to hypercoagulable states and hyperviscosity such as antithrombin iii deficiency, factor v leiden, protein c deficiency, antiphospholipid syndrome and malignancy 5. known history of selective iga deficiency with antibodies against iga 6. subjects with conditions such as human immunodeficiency virus (hiv) infection, known acute or chronic hepatitis b or c (hbsag positive or hcv ribonucleic acid (rna) pcr positive or currently treated with antivirals), pulmonary fibrosis, elevated procalcitonin (> 0.5) with concomitant neutrophilia (elevated polys), heparin induced thrombocytopenia (hit), and moderate to severe renal dysfunction (per investigator discretion based on estimated glomerular filtration rate [egfr] <59 ml/min/1.73 m2, as defined by kdigo clinical practice guideline): - moderately reduced gfr (g3a): gfr = 45 to 59 ml/min/1.73 m2 - moderately reduced gfr (g3b): gfr = 30 to 44 ml/min/1.73 m2 - severely reduced gfr (g4): gfr = 15 to 29 ml/min/1.73 m2 - kidney failure (g5): gfr <15 ml/min/1.73 m2 7. currently requiring imv (invasive mechanical ventilation or having received imv during the last 30 days 8. known clinically significant preexisting lung, heart, or neuromuscular disease that, in the investigator's opinion, would impact subject's ability to complete study or may confound the study results 9. body weight >125 kg 10. women who are pregnant or breast-feeding 11. subjects who received covid-19 convalescent plasma, ivig products, anti-interleukin agents (eg, tocilizumab), or interferons for their covid-19 disease before enrollment or plan to receive this treatment during the course of the study 12. enrolled in other experimental interventional studies or taking experimental medications (ie, convalescent plasma). diagnostic studies can be allowed if the anticipated total blood volume to be drawn across both studies and for therapeutic purposes does not exceed 450 ml over any 8-week period.

1. existence of other evidence that can explain pneumonia including but not limited to: influenza a virus, influenza b virus, bacterial pneumonia (as suggested by the combined clinical picture, radiological findings and known laboratory results [eg, elevated procalcitonin >0.5ng/ml and concomitant neutrophilia]), known fungal pneumonia, suspected fungal pneumonia based on compromised immune system with a history of past fungal infections, noninfectious causes, etc. 2. known history of serious allergic reactions, including anaphylaxis, to ivig or its preparation components 3. subjects with a history of thromboembolic event (tee) within the last 12 months, such as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, transient ischemic attack, peripheral artery disease (fontaine iv) 4. subjects with an underlying medical condition that can lead to hypercoagulable states and hyperviscosity such as antithrombin iii deficiency, factor v leiden, protein c deficiency, antiphospholipid syndrome and malignancy 5. known history of selective iga deficiency with antibodies against iga 6. subjects with conditions such as human immunodeficiency virus (hiv) infection, known acute or chronic hepatitis b or c (hbsag positive or hcv ribonucleic acid (rna) pcr positive or currently treated with antivirals), pulmonary fibrosis, elevated procalcitonin (> 0.5) with concomitant neutrophilia (elevated polys), heparin induced thrombocytopenia (hit), and moderate to severe renal dysfunction (per investigator discretion based on estimated glomerular filtration rate [egfr] <59 ml/min/1.73 m2, as defined by kdigo clinical practice guideline): - moderately reduced gfr (g3a): gfr = 45 to 59 ml/min/1.73 m2 - moderately reduced gfr (g3b): gfr = 30 to 44 ml/min/1.73 m2 - severely reduced gfr (g4): gfr = 15 to 29 ml/min/1.73 m2 - kidney failure (g5): gfr <15 ml/min/1.73 m2 7. currently requiring imv (invasive mechanical ventilation or having received imv during the last 30 days 8. known clinically significant preexisting lung, heart, or neuromuscular disease that, in the investigator's opinion, would impact subject's ability to complete study or may confound the study results 9. body weight >125 kg 10. women who are pregnant or breast-feeding 11. subjects who received covid-19 convalescent plasma, ivig products, anti-interleukin agents (eg, tocilizumab), or interferons for their covid-19 disease before enrollment or plan to receive this treatment during the course of the study 12. enrolled in other experimental interventional studies or taking experimental medications (ie, convalescent plasma). diagnostic studies can be allowed if the anticipated total blood volume to be drawn across both studies and for therapeutic purposes does not exceed 450 ml over any 8-week period.