1. unable or unwilling to take znag liquid solution or matching placebo as directed. 2. hospitalized prior to baseline for covid-19 management. 3. need for hospitalization and/or ventilatory support at baseline. 4. the emergence of any disease during study, other than covid-19 that could better explain the participants' signs and symptoms. 5. severe disease: respiratory distress, or requiring supplemental oxygen, or spo2 ≤ 93% on room air, or tachypnea (respiratory rate ≥ 30 breaths/min) at baseline. 6. history or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (nyha class 3 or 4). 7. legal incapacity or limited legal capacity. 8. women of childbearing potential who do not agree to use either abstinence or at least one primary form of contraception, not including hormonal contraception from the time of screening through the end of the study. 9. pregnant or breastfeeding. 10. participation in another clinical study with an investigational product within the prior 12 months (per resolution 251/1997).

1. unable or unwilling to take znag liquid solution or matching placebo as directed. 2. hospitalized prior to baseline for covid-19 management. 3. need for hospitalization and/or ventilatory support at baseline. 4. the emergence of any disease during study, other than covid-19 that could better explain the participants' signs and symptoms. 5. severe disease: respiratory distress, or requiring supplemental oxygen, or spo2 ≤ 93% on room air, or tachypnea (respiratory rate ≥ 30 breaths/min) at baseline. 6. history or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (nyha class 3 or 4). 7. legal incapacity or limited legal capacity. 8. women of childbearing potential who do not agree to use either abstinence or at least one primary form of contraception, not including hormonal contraception from the time of screening through the end of the study. 9. pregnant or breastfeeding. 10. participation in another clinical study with an investigational product within the prior 12 months (per resolution 251/1997).

unable or unwilling to take znag liquid solution or matching placebo as directed. hospitalized prior to baseline for covid-19 management. need for hospitalization and/or ventilatory support at baseline. the emergence of any disease during study, other than covid-19 that could better explain the participants' signs and symptoms. severe disease: respiratory distress, or requiring supplemental oxygen, or spo2 ≤ 93% on room air, or tachypnea (respiratory rate ≥ 30 breaths/min) at baseline. history or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (nyha class 3 or 4). legal incapacity or limited legal capacity. women of childbearing potential who do not agree to use either abstinence or at least one primary form of contraception, not including hormonal contraception from the time of screening through the end of the study. pregnant or breastfeeding. participation in another clinical study with an investigational product within the prior 12 months (per resolution 251/1997).

unable or unwilling to take znag liquid solution or matching placebo as directed. hospitalized prior to baseline for covid-19 management. need for hospitalization and/or ventilatory support at baseline. the emergence of any disease during study, other than covid-19 that could better explain the participants' signs and symptoms. severe disease: respiratory distress, or requiring supplemental oxygen, or spo2 ≤ 93% on room air, or tachypnea (respiratory rate ≥ 30 breaths/min) at baseline. history or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (nyha class 3 or 4). legal incapacity or limited legal capacity. women of childbearing potential who do not agree to use either abstinence or at least one primary form of contraception, not including hormonal contraception from the time of screening through the end of the study. pregnant or breastfeeding. participation in another clinical study with an investigational product within the prior 12 months (per resolution 251/1997).

1. unable or unwilling to take znag liquid solution or matching placebo as directed. 2. hospitalized prior to baseline for covid-19 management. 3. need for hospitalization and/or ventilatory support at baseline. 4. the emergence of any disease during study, other than covid-19 that could better explain the participants' signs and symptoms. 5. severe disease: respiratory distress, or requiring supplemental oxygen, or spo2 ≤ 93% on room air, or tachypnea (respiratory rate ≥ 30 breaths/min) at baseline. 6. history or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (nyha class 3 or 4). 7. legal incapacity or limited legal capacity. 8. women of childbearing potential who do not agree to use either abstinence or at least one primary form of contraception, not including hormonal contraception from the time of screening through the end of the study. 9. pregnant or breastfeeding. 10. participation in another clinical study with an investigational product within the prior 12 months (per resolution 251/1997).

1. unable or unwilling to take znag liquid solution or matching placebo as directed. 2. hospitalized prior to baseline for covid-19 management. 3. need for hospitalization and/or ventilatory support at baseline. 4. the emergence of any disease during study, other than covid-19 that could better explain the participants' signs and symptoms. 5. severe disease: respiratory distress, or requiring supplemental oxygen, or spo2 ≤ 93% on room air, or tachypnea (respiratory rate ≥ 30 breaths/min) at baseline. 6. history or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (nyha class 3 or 4). 7. legal incapacity or limited legal capacity. 8. women of childbearing potential who do not agree to use either abstinence or at least one primary form of contraception, not including hormonal contraception from the time of screening through the end of the study. 9. pregnant or breastfeeding. 10. participation in another clinical study with an investigational product within the prior 12 months (per resolution 251/1997).