1. known or suspected allergies to the components of azivudine tablets; 2. according to the latest version of the national health and medical commission diagnostic criteria of covid-19, patients with severe novel coronavirus pneumonia was confirmed; 3. severe liver disease (tbil\>=2 times normal upper limit; altast\>=5 times normal upper limit); 4. subjects with severe renal insufficiency (glomerular filtration rate ≤60 ml/min/1.73 m2) or undergoing continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 5. subjects with complication of malabsorption syndrome or any other condition affecting gastrointestinal absorption, requiring intravenous nutrition or not being able to take drugs orally; 6. subjectsis currently receiving anti-hiv treatment; 7. women who are breast-feeding during pregnancy or have a family plan during the trial period and within 6 months after the end of the trial; 8. participating in other clinical trials or using experimental drugs, except traditional chinese medicine; 9. other conditions that not appropriate to be enrolled into this study based on investigator's advise.

1. known or suspected allergies to the components of azivudine tablets; 2. according to the latest version of the national health and medical commission diagnostic criteria of covid-19, patients with severe novel coronavirus pneumonia was confirmed; 3. severe liver disease (tbil\>=2 times normal upper limit; altast\>=5 times normal upper limit); 4. subjects with severe renal insufficiency (glomerular filtration rate ≤60 ml/min/1.73 m2) or undergoing continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 5. subjects with complication of malabsorption syndrome or any other condition affecting gastrointestinal absorption, requiring intravenous nutrition or not being able to take drugs orally; 6. subjectsis currently receiving anti-hiv treatment; 7. women who are breast-feeding during pregnancy or have a family plan during the trial period and within 6 months after the end of the trial; 8. participating in other clinical trials or using experimental drugs, except traditional chinese medicine; 9. other conditions that not appropriate to be enrolled into this study based on investigator's advise.

known or suspected allergies to the components of azivudine tablets; according to the latest version of the national health and medical commission diagnostic criteria of covid-19, patients with severe novel coronavirus pneumonia was confirmed; severe liver disease (tbil>=2 times normal upper limit; altast>=5 times normal upper limit); subjects with severe renal insufficiency (glomerular filtration rate ≤60 ml/min/1.73 m2) or undergoing continuous renal replacement therapy, hemodialysis or peritoneal dialysis; subjects with complication of malabsorption syndrome or any other condition affecting gastrointestinal absorption, requiring intravenous nutrition or not being able to take drugs orally; subjectsis currently receiving anti-hiv treatment; women who are breast-feeding during pregnancy or have a family plan during the trial period and within 6 months after the end of the trial; participating in other clinical trials or using experimental drugs, except traditional chinese medicine; other conditions that not appropriate to be enrolled into this study based on investigator's advise.

known or suspected allergies to the components of azivudine tablets; according to the latest version of the national health and medical commission diagnostic criteria of covid-19, patients with severe novel coronavirus pneumonia was confirmed; severe liver disease (tbil>=2 times normal upper limit; altast>=5 times normal upper limit); subjects with severe renal insufficiency (glomerular filtration rate ≤60 ml/min/1.73 m2) or undergoing continuous renal replacement therapy, hemodialysis or peritoneal dialysis; subjects with complication of malabsorption syndrome or any other condition affecting gastrointestinal absorption, requiring intravenous nutrition or not being able to take drugs orally; subjectsis currently receiving anti-hiv treatment; women who are breast-feeding during pregnancy or have a family plan during the trial period and within 6 months after the end of the trial; participating in other clinical trials or using experimental drugs, except traditional chinese medicine; other conditions that not appropriate to be enrolled into this study based on investigator's advise.

1. known or suspected allergies to the components of azivudine tablets; 2. according to the latest version of the national health and medical commission diagnostic criteria of covid-19, patients with severe novel coronavirus pneumonia was confirmed; 3. severe liver disease (tbil>=2 times normal upper limit; altast>=5 times normal upper limit); 4. subjects with severe renal insufficiency (glomerular filtration rate ≤60 ml/min/1.73 m2) or undergoing continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 5. subjects with complication of malabsorption syndrome or any other condition affecting gastrointestinal absorption, requiring intravenous nutrition or not being able to take drugs orally; 6. subjectsis currently receiving anti-hiv treatment; 7. women who are breast-feeding during pregnancy or have a family plan during the trial period and within 6 months after the end of the trial; 8. participating in other clinical trials or using experimental drugs, except traditional chinese medicine; 9. other conditions that not appropriate to be enrolled into this study based on investigator's advise.

1. known or suspected allergies to the components of azivudine tablets; 2. according to the latest version of the national health and medical commission diagnostic criteria of covid-19, patients with severe novel coronavirus pneumonia was confirmed; 3. severe liver disease (tbil>=2 times normal upper limit; altast>=5 times normal upper limit); 4. subjects with severe renal insufficiency (glomerular filtration rate ≤60 ml/min/1.73 m2) or undergoing continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 5. subjects with complication of malabsorption syndrome or any other condition affecting gastrointestinal absorption, requiring intravenous nutrition or not being able to take drugs orally; 6. subjectsis currently receiving anti-hiv treatment; 7. women who are breast-feeding during pregnancy or have a family plan during the trial period and within 6 months after the end of the trial; 8. participating in other clinical trials or using experimental drugs, except traditional chinese medicine; 9. other conditions that not appropriate to be enrolled into this study based on investigator's advise.