1. those with known or suspected hypersensitivity to es16001 or any of its excipients 2. those with genetic issues with galactose intolerance, lapp lactase deficiency, or glucose-galactose malabsorption, etc. 3. patients with ecg evidence of a qtcf \> 450 ms in men and \> 470 ms in women and patients with any other risk factors for torsades de pointes (tdp) (hypokalemia, hypomagnesemia or hypocalcemia, family history of long qt syndrome, low left ventricular ejection fraction, left ventricular hypertrophy, ischemia and slow heart rate) 4. concomitant use of hydroxychloroquine or other drugs known to prolong qt interval throughout the study 5. suspected active bacterial, fungal, viral, or other infection (besides covid-19). 6. immunosuppressor or immunomodulatory drugs within the past 3 months (excluding corticosteroids) and patients with autoimmune disease. 7. patients with one of the following severe covid-19 signs at randomization (based on nih classification) * oxygen saturation (spo2) \<94% of oxygen saturation without oxygen supply in room air * partial pressure of oxygen/fraction of inspired oxygen (pao2/fio2) \<300 mmhg * respiratory frequency \>30 times/min * parenchyma infiltration\> 50% 8. patients requiring oxygen treatment (nasal prong, facial mask, and high flow oxygen) or machine respiration (oxygen by niv or high flow, intubation and mechanical ventilation, and etc.) at randomization 9. those requiring extracorporeal membrane oxygenation (ecmo) or continuous renal replacement therapy (crrt) treatment due to damage on multiple organs with severe illness (respiratory failure, shock, or multiple organ disorder) 10. those with issues on kidney or liver as follows in the screening 1. alanine transaminase (alt) or aspartate aminotransferase (ast) \> 5 x upper limit of normal (uln) at screening 2. total bilirubin that is 1.5 x upper limit of normal (uln) at screening in the blood 3. serum creatine \> 2mg/dl (\> 176.8 μmol/l) or estimated creatine clearance \< 30ml/min measured or calculated by cockroft gault equation 11. absolute neutrophil count (anc) \<1000/μl in the screening 12. platelet count \<50,000/μl in the screening 13. those who are pregnant or breastfeeding 14. treatment with an investigational product within 5 times half-life or to 30 days from the screening (whichever is longer) 15. those taking antiviral drugs, anti-inflammatory medicine, or neutralizing antibody that is known to influence the treatment of covid-19 (refer to 7.4.2 prohibited medication) 16. those with chronic disease that is inappropriate for the participation in clinical study judged by the investigator (uncontrolled diabetes, chronic kidney disease, chronic liver disease, chronic lung disease, chronic cardiovascular disease, blood cancer, chemotherapeutic cancer patients, patients taking immunosuppressants, idiopathic thrombocytopenia, hyperkalemia patients, etc.)

1. those with known or suspected hypersensitivity to es16001 or any of its excipients 2. those with genetic issues with galactose intolerance, lapp lactase deficiency, or glucose-galactose malabsorption, etc. 3. patients with ecg evidence of a qtcf \> 450 ms in men and \> 470 ms in women and patients with any other risk factors for torsades de pointes (tdp) (hypokalemia, hypomagnesemia or hypocalcemia, family history of long qt syndrome, low left ventricular ejection fraction, left ventricular hypertrophy, ischemia and slow heart rate) 4. concomitant use of hydroxychloroquine or other drugs known to prolong qt interval throughout the study 5. suspected active bacterial, fungal, viral, or other infection (besides covid-19). 6. immunosuppressor or immunomodulatory drugs within the past 3 months (excluding corticosteroids) and patients with autoimmune disease. 7. patients with one of the following severe covid-19 signs at randomization (based on nih classification) * oxygen saturation (spo2) \<94% of oxygen saturation without oxygen supply in room air * partial pressure of oxygen/fraction of inspired oxygen (pao2/fio2) \<300 mmhg * respiratory frequency \>30 times/min * parenchyma infiltration\> 50% 8. patients requiring oxygen treatment (nasal prong, facial mask, and high flow oxygen) or machine respiration (oxygen by niv or high flow, intubation and mechanical ventilation, and etc.) at randomization 9. those requiring extracorporeal membrane oxygenation (ecmo) or continuous renal replacement therapy (crrt) treatment due to damage on multiple organs with severe illness (respiratory failure, shock, or multiple organ disorder) 10. those with issues on kidney or liver as follows in the screening 1. alanine transaminase (alt) or aspartate aminotransferase (ast) \> 5 x upper limit of normal (uln) at screening 2. total bilirubin that is 1.5 x upper limit of normal (uln) at screening in the blood 3. serum creatine \> 2mg/dl (\> 176.8 μmol/l) or estimated creatine clearance \< 30ml/min measured or calculated by cockroft gault equation 11. absolute neutrophil count (anc) \<1000/μl in the screening 12. platelet count \<50,000/μl in the screening 13. those who are pregnant or breastfeeding 14. treatment with an investigational product within 5 times half-life or to 30 days from the screening (whichever is longer) 15. those taking antiviral drugs, anti-inflammatory medicine, or neutralizing antibody that is known to influence the treatment of covid-19 (refer to 7.4.2 prohibited medication) 16. those with chronic disease that is inappropriate for the participation in clinical study judged by the investigator (uncontrolled diabetes, chronic kidney disease, chronic liver disease, chronic lung disease, chronic cardiovascular disease, blood cancer, chemotherapeutic cancer patients, patients taking immunosuppressants, idiopathic thrombocytopenia, hyperkalemia patients, etc.)

those with known or suspected hypersensitivity to es16001 or any of its excipients those with genetic issues with galactose intolerance, lapp lactase deficiency, or glucose-galactose malabsorption, etc. patients with ecg evidence of a qtcf > 450 ms in men and > 470 ms in women and patients with any other risk factors for torsades de pointes (tdp) (hypokalemia, hypomagnesemia or hypocalcemia, family history of long qt syndrome, low left ventricular ejection fraction, left ventricular hypertrophy, ischemia and slow heart rate) concomitant use of hydroxychloroquine or other drugs known to prolong qt interval throughout the study 5. suspected active bacterial, fungal, viral, or other infection (besides covid-19). 6. immunosuppressor or immunomodulatory drugs within the past 3 months (excluding corticosteroids) and patients with autoimmune disease. 7. patients with one of the following severe covid-19 signs at randomization (based on nih classification) oxygen saturation (spo2) <94% of oxygen saturation without oxygen supply in room air partial pressure of oxygen/fraction of inspired oxygen (pao2/fio2) <300 mmhg respiratory frequency >30 times/min parenchyma infiltration> 50% 8. patients requiring oxygen treatment (nasal prong, facial mask, and high flow oxygen) or machine respiration (oxygen by niv or high flow, intubation and mechanical ventilation, and etc.) at randomization 9. those requiring extracorporeal membrane oxygenation (ecmo) or continuous renal replacement therapy (crrt) treatment due to damage on multiple organs with severe illness (respiratory failure, shock, or multiple organ disorder) 10. those with issues on kidney or liver as follows in the screening alanine transaminase (alt) or aspartate aminotransferase (ast) > 5 x upper limit of normal (uln) at screening total bilirubin that is 1.5 x upper limit of normal (uln) at screening in the blood serum creatine > 2mg/dl (> 176.8 μmol/l) or estimated creatine clearance < 30ml/min measured or calculated by cockroft gault equation 11. absolute neutrophil count (anc) <1000/μl in the screening 12. platelet count <50,000/μl in the screening 13. those who are pregnant or breastfeeding 14. treatment with an investigational product within 5 times half-life or to 30 days from the screening (whichever is longer) 15. those taking antiviral drugs, anti-inflammatory medicine, or neutralizing antibody that is known to influence the treatment of covid-19 (refer to 7.4.2 prohibited medication) 16. those with chronic disease that is inappropriate for the participation in clinical study judged by the investigator (uncontrolled diabetes, chronic kidney disease, chronic liver disease, chronic lung disease, chronic cardiovascular disease, blood cancer, chemotherapeutic cancer patients, patients taking immunosuppressants, idiopathic thrombocytopenia, hyperkalemia patients, etc.)

those with known or suspected hypersensitivity to es16001 or any of its excipients those with genetic issues with galactose intolerance, lapp lactase deficiency, or glucose-galactose malabsorption, etc. patients with ecg evidence of a qtcf > 450 ms in men and > 470 ms in women and patients with any other risk factors for torsades de pointes (tdp) (hypokalemia, hypomagnesemia or hypocalcemia, family history of long qt syndrome, low left ventricular ejection fraction, left ventricular hypertrophy, ischemia and slow heart rate) concomitant use of hydroxychloroquine or other drugs known to prolong qt interval throughout the study 5. suspected active bacterial, fungal, viral, or other infection (besides covid-19). 6. immunosuppressor or immunomodulatory drugs within the past 3 months (excluding corticosteroids) and patients with autoimmune disease. 7. patients with one of the following severe covid-19 signs at randomization (based on nih classification) oxygen saturation (spo2) <94% of oxygen saturation without oxygen supply in room air partial pressure of oxygen/fraction of inspired oxygen (pao2/fio2) <300 mmhg respiratory frequency >30 times/min parenchyma infiltration> 50% 8. patients requiring oxygen treatment (nasal prong, facial mask, and high flow oxygen) or machine respiration (oxygen by niv or high flow, intubation and mechanical ventilation, and etc.) at randomization 9. those requiring extracorporeal membrane oxygenation (ecmo) or continuous renal replacement therapy (crrt) treatment due to damage on multiple organs with severe illness (respiratory failure, shock, or multiple organ disorder) 10. those with issues on kidney or liver as follows in the screening alanine transaminase (alt) or aspartate aminotransferase (ast) > 5 x upper limit of normal (uln) at screening total bilirubin that is 1.5 x upper limit of normal (uln) at screening in the blood serum creatine > 2mg/dl (> 176.8 μmol/l) or estimated creatine clearance < 30ml/min measured or calculated by cockroft gault equation 11. absolute neutrophil count (anc) <1000/μl in the screening 12. platelet count <50,000/μl in the screening 13. those who are pregnant or breastfeeding 14. treatment with an investigational product within 5 times half-life or to 30 days from the screening (whichever is longer) 15. those taking antiviral drugs, anti-inflammatory medicine, or neutralizing antibody that is known to influence the treatment of covid-19 (refer to 7.4.2 prohibited medication) 16. those with chronic disease that is inappropriate for the participation in clinical study judged by the investigator (uncontrolled diabetes, chronic kidney disease, chronic liver disease, chronic lung disease, chronic cardiovascular disease, blood cancer, chemotherapeutic cancer patients, patients taking immunosuppressants, idiopathic thrombocytopenia, hyperkalemia patients, etc.)