Inclusion Criteria:  Is a male or female greater than or equal to18 years of age at Screening; Is willing and able to sign and date (or has a legally authorized representative willing to sign and date) a written (or electronic) informed consent form or provide equivalent consent per Food and Drug Administration guidelines on COVID-19 clinical trials; Has a documented, laboratory-confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection as determined by polymerase chain reaction, a SARS-CoV-2 antigen test, or another commercial or public health assay, within 3 days (72 hours) of randomization; Has COVID-19 of moderate severity, as defined by the following: Positive testing by standard reverse transcription polymerase chain reaction assay or equivalent testing; Symptoms of illness with COVID-19, which could include any of the following: cough, fever, shortness of breath, chest pain, abdominal pain, nausea/vomiting, diarrhea, body aches, weakness/fatigue, or new loss of taste or smell; Clinical signs suggestive of illness with COVID-19, such as respiratory rate greater than or equal to 20 breaths per minute, saturation of oxygen greater than 93% on room air at sea level, or heart rate greater than or equal to 90 beats per minute; and No clinical signs indicative of severe or critical severity.  Exclusion Criteria:  Has an NIAID ordinal scale score <5; Is on high-flow oxygen or any form of noninvasive ventilation, excluding continuous positive airway pressure (CPAP) alone for sleep disorders (e.g., obstructive sleep apnea); Has significant cardiovascular disease, defined by myocardial infarction, arterial thromboembolism, or cerebrovascular thromboembolism within 3 months prior to randomization; symptomatic dysrhythmias or unstable dysrhythmias requiring medical therapy; angina requiring therapy; symptomatic peripheral vascular disease; New York Heart Association Class 3 or 4 congestive heart failure; Grade 3 hypertension (diastolic blood pressure greater than or equal to 100 mmHg or systolic blood pressure greater than or equal to 160 mmHg); history of congenital prolonged QT syndrome, or known dyslipidemia; Is currently taking any investigational products, other than the study drug; Has any other condition that, in the opinion of the Investigator, could interfere with (or for which the treatment might interfere with) the conduct of the clinical trial or interpretation of the clinical trial results or that would place the subject at undue risk by participating in the clinical trial.