subject who meets any of the following criteria will be excluded from the trial: 1. subjects already progressed into critically severe covid-19 critical severe standards refer to fda guidelines,as shown in appendix 4 or sepsis and sepsis shock. 2. concomitant with the following situation:severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; severe cardiovascular and cerebrovascular disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification), or had undergone heart surgery within 6 months before randomization; severe liver diseases (e.g. child-pugh score ≥ grade c); severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m\^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. 3. subjects on current treatment with a complement inhibitor such as eculizumab within 1 month before randomization. 4. subjects with hypersensitivity history to any ingredient contained in the drug. 5. a subject has used the following drugs within 2 weeks prior to screening procedures: * calcineurin inhibitors (e.g., ciclosporin, tacrolimus, etc.) * proliferation inhibitors (e.g., everolimus, sirolimus, etc.) * anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) * recombinant human granulocyte macrophage colony stimulating factor (rhgm-csf)/recombinant human granulocyte colony stimulating factor (rhg-csf) 6. pregnant or lactating woman. 7. subjects who have participated in other interventional clinical trials in the last 3 months or during this trial. 8. any other circumstances that the investigator considers inappropriate for the participation in this study.

subject who meets any of the following criteria will be excluded from the trial: 1. subjects already progressed into critically severe covid-19 critical severe standards refer to fda guidelines,as shown in appendix 4 or sepsis and sepsis shock. 2. concomitant with the following situation:severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; severe cardiovascular and cerebrovascular disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification), or had undergone heart surgery within 6 months before randomization; severe liver diseases (e.g. child-pugh score ≥ grade c); severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m\^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. 3. subjects on current treatment with a complement inhibitor such as eculizumab within 1 month before randomization. 4. subjects with hypersensitivity history to any ingredient contained in the drug. 5. a subject has used the following drugs within 2 weeks prior to screening procedures: * calcineurin inhibitors (e.g., ciclosporin, tacrolimus, etc.) * proliferation inhibitors (e.g., everolimus, sirolimus, etc.) * anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) * recombinant human granulocyte macrophage colony stimulating factor (rhgm-csf)/recombinant human granulocyte colony stimulating factor (rhg-csf) 6. pregnant or lactating woman. 7. subjects who have participated in other interventional clinical trials in the last 3 months or during this trial. 8. any other circumstances that the investigator considers inappropriate for the participation in this study.

subject who meets any of the following criteria will be excluded from the trial: subjects already progressed into critically severe covid-19 critical severe standards refer to fda guidelines,as shown in appendix 4 or sepsis and sepsis shock. concomitant with the following situation:severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; severe cardiovascular and cerebrovascular disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification), or had undergone heart surgery within 6 months before randomization; severe liver diseases (e.g. child-pugh score ≥ grade c); severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. subjects on current treatment with a complement inhibitor such as eculizumab within 1 month before randomization. subjects with hypersensitivity history to any ingredient contained in the drug. a subject has used the following drugs within 2 weeks prior to screening procedures: calcineurin inhibitors (e.g., ciclosporin, tacrolimus, etc.) proliferation inhibitors (e.g., everolimus, sirolimus, etc.) anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) recombinant human granulocyte macrophage colony stimulating factor (rhgm-csf)/recombinant human granulocyte colony stimulating factor (rhg-csf) pregnant or lactating woman. subjects who have participated in other interventional clinical trials in the last 3 months or during this trial. any other circumstances that the investigator considers inappropriate for the participation in this study.

subject who meets any of the following criteria will be excluded from the trial: subjects already progressed into critically severe covid-19 critical severe standards refer to fda guidelines,as shown in appendix 4 or sepsis and sepsis shock. concomitant with the following situation:severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; severe cardiovascular and cerebrovascular disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification), or had undergone heart surgery within 6 months before randomization; severe liver diseases (e.g. child-pugh score ≥ grade c); severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. subjects on current treatment with a complement inhibitor such as eculizumab within 1 month before randomization. subjects with hypersensitivity history to any ingredient contained in the drug. a subject has used the following drugs within 2 weeks prior to screening procedures: calcineurin inhibitors (e.g., ciclosporin, tacrolimus, etc.) proliferation inhibitors (e.g., everolimus, sirolimus, etc.) anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) recombinant human granulocyte macrophage colony stimulating factor (rhgm-csf)/recombinant human granulocyte colony stimulating factor (rhg-csf) pregnant or lactating woman. subjects who have participated in other interventional clinical trials in the last 3 months or during this trial. any other circumstances that the investigator considers inappropriate for the participation in this study.

subject who meets any of the following criteria will be excluded from the trial: 1. subjects already progressed into critically severe covid-19 critical severe standards refer to fda guidelines,as shown in appendix 4 or sepsis and sepsis shock. 2. concomitant with the following situation:severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; severe cardiovascular and cerebrovascular disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification), or had undergone heart surgery within 6 months before randomization; severe liver diseases (e.g. child-pugh score ≥ grade c); severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. 3. subjects on current treatment with a complement inhibitor such as eculizumab within 1 month before randomization. 4. subjects with hypersensitivity history to any ingredient contained in the drug. 5. a subject has used the following drugs within 2 weeks prior to screening procedures: - calcineurin inhibitors (e.g., ciclosporin, tacrolimus, etc.) - proliferation inhibitors (e.g., everolimus, sirolimus, etc.) - anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) - recombinant human granulocyte macrophage colony stimulating factor (rhgm-csf)/recombinant human granulocyte colony stimulating factor (rhg-csf) 6. pregnant or lactating woman. 7. subjects who have participated in other interventional clinical trials in the last 3 months or during this trial. 8. any other circumstances that the investigator considers inappropriate for the participation in this study.

subject who meets any of the following criteria will be excluded from the trial: 1. subjects already progressed into critically severe covid-19 critical severe standards refer to fda guidelines,as shown in appendix 4 or sepsis and sepsis shock. 2. concomitant with the following situation:severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; severe cardiovascular and cerebrovascular disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification), or had undergone heart surgery within 6 months before randomization; severe liver diseases (e.g. child-pugh score ≥ grade c); severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. 3. subjects on current treatment with a complement inhibitor such as eculizumab within 1 month before randomization. 4. subjects with hypersensitivity history to any ingredient contained in the drug. 5. a subject has used the following drugs within 2 weeks prior to screening procedures: - calcineurin inhibitors (e.g., ciclosporin, tacrolimus, etc.) - proliferation inhibitors (e.g., everolimus, sirolimus, etc.) - anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) - recombinant human granulocyte macrophage colony stimulating factor (rhgm-csf)/recombinant human granulocyte colony stimulating factor (rhg-csf) 6. pregnant or lactating woman. 7. subjects who have participated in other interventional clinical trials in the last 3 months or during this trial. 8. any other circumstances that the investigator considers inappropriate for the participation in this study.

1. subjects already progressed into critically severe covid-19 (including respiratory failure requiring invasive mechanical ventilation, or shock, or combined with other organ failure which requires icu administration) or sepsis and sepsis shock. 2. history of severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; history of severe heart disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification); history of severe liver diseases (e.g. child-pugh score ≥ grade c); history of severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. 3. subjects on current treatment with a complement inhibitor such as eculizumab. 4. subjects with hypersensitivity history to any ingredient contained in the drug. 5. a subject has used the following drugs within 2 weeks prior to screening procedures: - immunesuppressive medicines (e.g., ciclosporin, tacrolimus, etc.) - proliferation inhibitors (e.g., everolimus, sirolimus, etc.) - anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) 6. pregnant or lactating woman. 7. subjects who have participated in other clinical trials in the last 3 months or during this trial. 8. any other circumstances that the investigator considers inappropriate for the participation in this study.

1. subjects already progressed into critically severe covid-19 (including respiratory failure requiring invasive mechanical ventilation, or shock, or combined with other organ failure which requires icu administration) or sepsis and sepsis shock. 2. history of severe lung disease such as chronic obstructive pulmonary disease (moderate to severe type), lung cancers, active tuberculosis; history of severe heart disease: unstable angina pectoris, myocardial infarction, postcardiac surgery, cardiac function ≥ grade 3 (nyha classification); history of severe liver diseases (e.g. child-pugh score ≥ grade c); history of severe kidney diseases, such as renal insufficiency (gfr ≤ 15 ml/min/1.73m^2); immune deficiencies or immune-related diseases : including organ or bone marrow transplantation, some autoimmune diseases, igg4-related diseases, allergic alveolitis, vasculitis; malignancies. 3. subjects on current treatment with a complement inhibitor such as eculizumab. 4. subjects with hypersensitivity history to any ingredient contained in the drug. 5. a subject has used the following drugs within 2 weeks prior to screening procedures: - immunesuppressive medicines (e.g., ciclosporin, tacrolimus, etc.) - proliferation inhibitors (e.g., everolimus, sirolimus, etc.) - anti-metabolic drugs (e.g., mycophenolate mofetil, mycophenolate, purine sulphate, etc.) 6. pregnant or lactating woman. 7. subjects who have participated in other clinical trials in the last 3 months or during this trial. 8. any other circumstances that the investigator considers inappropriate for the participation in this study.