Study of TB006 in Outpatient Patients With Mild to Moderate COVID-19

Inclusion Criteria: 1. Willing and able to provide written informed consent prior to performing study procedures (or legally authorized representative able to provide consent on the patient's behalf). 2. Age ≥ 18 years 3. A positive Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection confirmed by polymerase chain reaction (PCR) test or an equivalent test ≤ 3 days before randomization 4. Patients with mild to moderate COVID-19 experiencing any of the following symptoms: * Mild (without shortness of breath or dyspnea): Fever, cough, sore throat, malaise, headache, muscle pain, gastrointestinal symptoms * Moderate: Any symptom of mild illness, shortness of breath with excursion, clinically suggestive of moderate illness with COVID-19, such as respiratory rate ≥ 20 breaths per minute, saturation of oxygen (SpO2) \> 93% on room air at sea level, heart rate ≥ 90 beats per minute 5. At low risk for progressing to severe COVID-19 and/or hospitalization. 6. Adequate organ function at screening as evidenced by: * Hemoglobin \> 10.9 g/dL * Absolute neutrophil count (ANC) \> 1.0 × 10\^9/L * Platelets \> 125 × 10\^9/L * Alanine Aminotransferase (ALT) or aspartate aminotransferase (AST) \< 1.25 × upper limit of normal (ULN) * Creatinine clearance \> 90 mL/min using the Cockcroft-Gault formula for patients ≥ 18 years of age \[Cockcroft 1976\] 7. Normal electrocardiogram with QTcF of ≤ 450 ms Exclusion Criteria: 1. Participation in any other clinical trial of an experimental treatment for COVID-19 2. Clinical signs indicative of Severe or Critical Illness Severity * SEVERE: * Any symptom of severe, systematic illness, including moderate illness, shortness of breath, or respiratory distress * Clinically suggestive of severe illness with COVID-19, such as respiratory rate ≥ 30 breaths per minute, heart rate ≥ 125 per minute, saturation of oxygen (SpO2) ≤ 93% on room air at sea level, or PaO2/FiO2 \< 300 * CRITICAL ILLNESS (one of the following): * Respiratory failure defined based on resource utilization requiring at least one of the following: 1. Endotracheal intubation and mechanical ventilation, oxygen delivered by high483 flow nasal cannula (heated, humidified, oxygen delivered via reinforced nasal cannula at flow rates \> 20 L/min with fraction of delivered oxygen ≥ 0.5) 2. Noninvasive positive pressure ventilation, ECMO, or clinical diagnosis of respiratory failure (i.e., clinical need for one of the preceding therapies, but preceding therapies not able to be administered in setting of resource limitation) * Shock (defined by systolic blood pressure \< 90 mm Hg, or diastolic blood pressure \< 60 mm Hg or requiring vasopressors) * Multi-organ dysfunction/failure 3. Have a history of a positive SARS-CoV-2 serology test 4. Evidence of shock (defined by systolic blood pressure \< 90 mm Hg, or diastolic blood pressure \< 60 mm Hg or requiring vasopressors) 5. Patients who are hospitalized due to COVID-19 6. Patients who required oxygen therapy due to COVID-19 7. Patients who required mechanical ventilation or anticipated impending need for mechanical ventilation 8. Receiving V-V ECMO ≥ 5 days, or any duration of V-A ECMO 9. Have a history of convalescent COVID-19 plasma treatment 10. Women who are pregnant or breastfeeding 11. Male or female of childbearing potential who has plans to become pregnant during the study period and for six months after the clinical study or who is not willing to take appropriate contraceptive measures (e.g., concomitant use of a spermicidal agent, barrier contraceptive, or/and intrauterine contraceptive) 12. Viral disease (HIV, HBV, HCV, etc.) other than COVID-19 that are not adequately controlled or require administration of other antiviral agents or medications that could potentially interact with TB006 13. Patients with a history or current evidence of any concomitant condition, therapy, or laboratory abnormality that, in the opinion of the investigator, might confound the results of the trial, interfere with the patient's participation and compliance