* severe or critical covid-19: grade 4 or grade 5 of clinical severity scale. * current hospitalization and/or hospitalization or emergency room visit in the past 14 days. * need for immediate hospitalization for any reason in the investigator's opinion. * severe liver disease as determined by values of alt and/or ast \>5x upper limit of normal (uln) and/or history of liver cirrhosis. * severe renal disease as determined by estimated creatinine clearance (cccl) \<30 ml/min or serum creatinine \>2 mg/dl (\>176.8 μmol/l) or ongoing renal dialysis. * absolute neutrophil count (anc) \< 1000/μl. * demyelinating and connective tissue disease. * active tuberculosis or suspected active bacterial, fungal, viral, or other infection (besides covid- 19). * any condition that in the investigator's opinion may be negatively affected by the study treatments and/or study procedures. * any condition, including psychiatric disorders, alcohol, or substance abuse, which in the investigator's opinion may interfere with completion of the study procedures. * any condition with life expectancy \<6 months in the investigator's opinion. * ongoing or planned pregnancy. * ongoing breast feeding. * history of life-threatening event in the 1 month before visit 1. * history of surgery in the 1 month before visit 1. * history of treatment with blood components in the 6 months before visit 1. * history of cancer treated with chemotherapy in the 6 months before visit 1. * history of solid organ transplant at any time before visit 1. * history of severe and/or serious allergic reaction to monoclonal antibodies or any component of mad0004j08, including anaphylaxis at any time before visit 1. * treatment with an investigational drug or vaccine within 5 half-lives or 30 days (whichever is longer) of randomization. * treatment at any time with monoclonal antibodies bamlanivimab, bamlanivimab + etesevimab combination, and casiribimab + imdevimab combination.

* severe or critical covid-19: grade 4 or grade 5 of clinical severity scale. * current hospitalization and/or hospitalization or emergency room visit in the past 14 days. * need for immediate hospitalization for any reason in the investigator's opinion. * severe liver disease as determined by values of alt and/or ast \>5x upper limit of normal (uln) and/or history of liver cirrhosis. * severe renal disease as determined by estimated creatinine clearance (cccl) \<30 ml/min or serum creatinine \>2 mg/dl (\>176.8 μmol/l) or ongoing renal dialysis. * absolute neutrophil count (anc) \< 1000/μl. * demyelinating and connective tissue disease. * active tuberculosis or suspected active bacterial, fungal, viral, or other infection (besides covid- 19). * any condition that in the investigator's opinion may be negatively affected by the study treatments and/or study procedures. * any condition, including psychiatric disorders, alcohol, or substance abuse, which in the investigator's opinion may interfere with completion of the study procedures. * any condition with life expectancy \<6 months in the investigator's opinion. * ongoing or planned pregnancy. * ongoing breast feeding. * history of life-threatening event in the 1 month before visit 1. * history of surgery in the 1 month before visit 1. * history of treatment with blood components in the 6 months before visit 1. * history of cancer treated with chemotherapy in the 6 months before visit 1. * history of solid organ transplant at any time before visit 1. * history of severe and/or serious allergic reaction to monoclonal antibodies or any component of mad0004j08, including anaphylaxis at any time before visit 1. * treatment with an investigational drug or vaccine within 5 half-lives or 30 days (whichever is longer) of randomization. * treatment at any time with monoclonal antibodies bamlanivimab, bamlanivimab + etesevimab combination, and casiribimab + imdevimab combination.

- severe or critical covid-19: grade 4 or grade 5 of clinical severity scale. - current hospitalization and/or hospitalization or emergency room visit in the past 14 days. - need for immediate hospitalization for any reason in the investigator's opinion. - severe liver disease as determined by values of alt and/or ast >5x upper limit of normal (uln) and/or history of liver cirrhosis. - severe renal disease as determined by estimated creatinine clearance (cccl) <30 ml/min or serum creatinine >2 mg/dl (>176.8 μmol/l) or ongoing renal dialysis. - absolute neutrophil count (anc) < 1000/μl. - demyelinating and connective tissue disease. - active tuberculosis or suspected active bacterial, fungal, viral, or other infection (besides covid- 19). - any condition that in the investigator's opinion may be negatively affected by the study treatments and/or study procedures. - any condition, including psychiatric disorders, alcohol, or substance abuse, which in the investigator's opinion may interfere with completion of the study procedures. - any condition with life expectancy <6 months in the investigator's opinion. - ongoing or planned pregnancy. - ongoing breast feeding. - history of life-threatening event in the 1 month before visit 1. - history of surgery in the 1 month before visit 1. - history of treatment with blood components in the 6 months before visit 1. - history of cancer treated with chemotherapy in the 6 months before visit 1. - history of solid organ transplant at any time before visit 1. - history of severe and/or serious allergic reaction to monoclonal antibodies or any component of mad0004j08, including anaphylaxis at any time before visit 1. - treatment with an investigational drug or vaccine within 5 half-lives or 30 days (whichever is longer) of randomization. - treatment at any time with monoclonal antibodies bamlanivimab, bamlanivimab + etesevimab combination, and casiribimab + imdevimab combination.

- severe or critical covid-19: grade 4 or grade 5 of clinical severity scale. - current hospitalization and/or hospitalization or emergency room visit in the past 14 days. - need for immediate hospitalization for any reason in the investigator's opinion. - severe liver disease as determined by values of alt and/or ast >5x upper limit of normal (uln) and/or history of liver cirrhosis. - severe renal disease as determined by estimated creatinine clearance (cccl) <30 ml/min or serum creatinine >2 mg/dl (>176.8 μmol/l) or ongoing renal dialysis. - absolute neutrophil count (anc) < 1000/μl. - demyelinating and connective tissue disease. - active tuberculosis or suspected active bacterial, fungal, viral, or other infection (besides covid- 19). - any condition that in the investigator's opinion may be negatively affected by the study treatments and/or study procedures. - any condition, including psychiatric disorders, alcohol, or substance abuse, which in the investigator's opinion may interfere with completion of the study procedures. - any condition with life expectancy <6 months in the investigator's opinion. - ongoing or planned pregnancy. - ongoing breast feeding. - history of life-threatening event in the 1 month before visit 1. - history of surgery in the 1 month before visit 1. - history of treatment with blood components in the 6 months before visit 1. - history of cancer treated with chemotherapy in the 6 months before visit 1. - history of solid organ transplant at any time before visit 1. - history of severe and/or serious allergic reaction to monoclonal antibodies or any component of mad0004j08, including anaphylaxis at any time before visit 1. - treatment with an investigational drug or vaccine within 5 half-lives or 30 days (whichever is longer) of randomization. - treatment at any time with monoclonal antibodies bamlanivimab, bamlanivimab + etesevimab combination, and casiribimab + imdevimab combination.