This is a multicenter, randomized, double-blind, placebo-parallel-controlled phase III clinical trial. It is designed to evaluate the efficacy and safety of SHEN26 capsules in Chinese adult patients with mild to moderate COVID-19

Inclusion Criteria:

1. Participants ≥18 years of age, male or female.
2. The subjects were classified as mild or moderate COVID-19, confirmed SARS-CoV-2 infection 72 hours prior to randomization.
3. Initial onset 2 of 11 COVID-19 symptoms within 72 hours before randomization, respiratory and feverish symptoms must be included.
4. Female subjects of childbearing age must have a negative urine pregnancy test during the screening.Fertile participants must agree to take effective contraceptive measures.
5. Understand the procedures and methods of this clinical trial, after fully informed and they participate voluntarily and sign the informed consent form.

Exclusion Criteria:

1. Known hypersensitivity to any ingredient in the experimental drug.
2. Patients with severe or critical COVID-19.
3. With abnormal liver function observed at the time of screening: total bilirubin ≥ 2 × upper limit of normal (ULN), or alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≥ 3 × ULN.
4. Subjects with liver diseases, including but not limited to the following diseases, which may affect the safety or efficacy evaluation of subjects during the trial as assessed by the investigator:primary biliary cirrhosis、Child-Pugh Class B or C、acute liver failure.
5. Subjects with known human immunodeficiency virus (HIV) infection.
6. Abnormal renal function observed at the time of screening: serum creatinine ≥ 1.5×ULN;or patients receiving continuous renal replacement therapy, hemodialysis, and peritoneal dialysis at the time of screening.
7. Subjects with acute exacerbation of chronic respiratory diseases.
8. Suspected or confirmed acute systemic infections other than COVID-19 observed at the time of screening.
9. Complications requiring surgery before randomized trial or during the entire trial period and major surgery operated 14 days before the randomized trial,or life-threatening comorbidities considered by the investigator within 30 days before the randomized trial.
10. Cardiovascular diseases meeting any of the following criteria:History of myocardial infarction within the past 12 months、Unstable angina、Clinically significant and uncontrollable cardiac arrhythmias、History of stroke or transient ischemic attack requiring drug treatment in the past 12 months、Congestive heart failure of grade ≥ II assessed by New York Heart Association (NYHA)、Localized edema of grade ≥3、Clinically uncontrolled hypertension.
11. Received SARS-CoV-2 monoclonal antibody treatment or prevention within 30 days before the randomized trial.
12. Received convalescent COVID-19 patient plasma or COVID-19 human immunoglobulin therapy within 30 days before the randomized trial.
13. Have taken antiviral drugs within 30 days before the randomized trial.
14. Have taken any COVID-19 vaccine within 3 months or have been infected with new coronavirus within 3 months before the randomized trial.
15. Pregnant and lactating women.
16. Have participated in other clinical trials or are using experimental drugs within 3 months before the randomized trial.
17. Under other conditions that are not suitable for participating in this trial assessed by the investigator.