inclusion criteria: 1. ≥18 and \<65 years of age when signing the icf, male or femal. 2. positive testing by virologic test (sars-cov-2 virus nucleic acid test,result of rt-pcr within 3 days are accpetable) before randomization. 3. covid-19 related clinical symptoms (fever or respiratory symptoms, etc.) progresses before randomization. 4. inpatients with moderate or severe covid-19 (severity is graded by fda standard). 5. with early warning signs for severe/critical cases, meet any of the following indicators: ①progressive exacerbation of hypoxemia or respiratory distress; ②deterioration of tissue oxygenation or progressive hyperlactatemia. ③ rapid decrease in lymphocyte count or steady increase in inflammatory markers such as il-6, crp, and ferritin. ④significant increase of d-dimer and other related indexes of coagulation function. ⑤chest imaging showing rapid progression of lung lesions. 6. randomization should be within 10 days of covid-19 symptoms onset. 7. subjects (including their partners) have no pregnancy plan and voluntarily take effective contraceptive measures from signing icf to 3 months after he/she finished the trial. 8. willing to comply with the requirements, and cooperate when collecting of nasopharyngeal swabs and venous blood for testing according to the protocol; and willing to complete the study. 9. able to consent, and willing to sign the icf.

inclusion criteria: 1. ≥18 and \<65 years of age when signing the icf, male or femal. 2. positive testing by virologic test (sars-cov-2 virus nucleic acid test,result of rt-pcr within 3 days are accpetable) before randomization. 3. covid-19 related clinical symptoms (fever or respiratory symptoms, etc.) progresses before randomization. 4. inpatients with moderate or severe covid-19 (severity is graded by fda standard). 5. with early warning signs for severe/critical cases, meet any of the following indicators: ①progressive exacerbation of hypoxemia or respiratory distress; ②deterioration of tissue oxygenation or progressive hyperlactatemia. ③ rapid decrease in lymphocyte count or steady increase in inflammatory markers such as il-6, crp, and ferritin. ④significant increase of d-dimer and other related indexes of coagulation function. ⑤chest imaging showing rapid progression of lung lesions. 6. randomization should be within 10 days of covid-19 symptoms onset. 7. subjects (including their partners) have no pregnancy plan and voluntarily take effective contraceptive measures from signing icf to 3 months after he/she finished the trial. 8. willing to comply with the requirements, and cooperate when collecting of nasopharyngeal swabs and venous blood for testing according to the protocol; and willing to complete the study. 9. able to consent, and willing to sign the icf.

inclusion criteria: ≥18 and <65 years of age when signing the icf, male or femal. positive testing by virologic test (sars-cov-2 virus nucleic acid test,result of rt-pcr within 3 days are accpetable) before randomization. covid-19 related clinical symptoms (fever or respiratory symptoms, etc.) progresses before randomization. inpatients with moderate or severe covid-19 (severity is graded by fda standard). with early warning signs for severe/critical cases, meet any of the following indicators: ①progressive exacerbation of hypoxemia or respiratory distress; ②deterioration of tissue oxygenation or progressive hyperlactatemia. ③ rapid decrease in lymphocyte count or steady increase in inflammatory markers such as il-6, crp, and ferritin. ④significant increase of d-dimer and other related indexes of coagulation function. ⑤chest imaging showing rapid progression of lung lesions. randomization should be within 10 days of covid-19 symptoms onset. subjects (including their partners) have no pregnancy plan and voluntarily take effective contraceptive measures from signing icf to 3 months after he/she finished the trial. willing to comply with the requirements, and cooperate when collecting of nasopharyngeal swabs and venous blood for testing according to the protocol; and willing to complete the study. able to consent, and willing to sign the icf.

inclusion criteria: ≥18 and <65 years of age when signing the icf, male or femal. positive testing by virologic test (sars-cov-2 virus nucleic acid test,result of rt-pcr within 3 days are accpetable) before randomization. covid-19 related clinical symptoms (fever or respiratory symptoms, etc.) progresses before randomization. inpatients with moderate or severe covid-19 (severity is graded by fda standard). with early warning signs for severe/critical cases, meet any of the following indicators: ①progressive exacerbation of hypoxemia or respiratory distress; ②deterioration of tissue oxygenation or progressive hyperlactatemia. ③ rapid decrease in lymphocyte count or steady increase in inflammatory markers such as il-6, crp, and ferritin. ④significant increase of d-dimer and other related indexes of coagulation function. ⑤chest imaging showing rapid progression of lung lesions. randomization should be within 10 days of covid-19 symptoms onset. subjects (including their partners) have no pregnancy plan and voluntarily take effective contraceptive measures from signing icf to 3 months after he/she finished the trial. willing to comply with the requirements, and cooperate when collecting of nasopharyngeal swabs and venous blood for testing according to the protocol; and willing to complete the study. able to consent, and willing to sign the icf.