1. Allergic constitution, known to be allergic to balosavir or farpiravir or pharmaceutical excipients, 2. Body weight <40 kg, 3. Considered as severe disease: has an ongoing respiratory deficiency and subjected to invasive mechanical ventilation, or presence of shock, or admitted to the ICU due to complications, 4. Has known kidney dysfunction determined as CLcr<60 mL/min, 5. Increase in alanine aminotransferase (ALT) / aspartate aminotransferase (AST) is more than 5 times the upper limit of normal, or increase in ALT or AST is more than 3 ULN and increase in total bilirubin more than 2 ULN, 6. In the investigator's judgment, there are other factors that may cause the subject to be forced to terminate the study, such as other serious illnesses, serious laboratory abnormalities, and other factors that may affect the safety of the subject or the collection of test data and blood samples.

1. Allergic constitution, known to be allergic to balosavir or farpiravir or pharmaceutical excipients, 2. Body weight <40 kg, 3. Considered as severe disease: has an ongoing respiratory deficiency and subjected to invasive mechanical ventilation, or presence of shock, or admitted to the ICU due to complications, 4. Has known kidney dysfunction determined as CLcr<60 mL/min, 5. Increase in alanine aminotransferase (ALT) / aspartate aminotransferase (AST) is more than 5 times the upper limit of normal, or increase in ALT or AST is more than 3 ULN and increase in total bilirubin more than 2 ULN, 6. In the investigator's judgment, there are other factors that may cause the subject to be forced to terminate the study, such as other serious illnesses, serious laboratory abnormalities, and other factors that may affect the safety of the subject or the collection of test data and blood samples.