High-dose Hydroxychloroquine for the Treatment of Ambulatory Patients With Mild COVID-19

Inclusion Criteria: * Being tested positive for SARS-Cov-2 in outpatient setting in drive-thru, ED, or ambulatory clinics at the University of Chicago within 72 hours of enrollment. * Age \>18 * Fever \>100.4 F by any conventional clinical method (forehead, tympanic, oral, axillary, rectal) within 48h prior to enrollment * Mild COVID-19, defined as the presence of any symptom consistent with an upper respiratory tract infection, including dry cough, sore throat, nasal congestion, fatigue, myalgia, headaches. Subjects must meet all the above-mentioned criteria, in addition to at least one of the following criteria: * Age \> 55 * Pre-existing pulmonary disease: airway diseases (asthma, chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis), history of active or treated lung cancer, history of pneumectomy, interstitial lung diseases, pulmonary hypertension, sleep apnea. * Diabetes: uncontrolled or controlled diabetes * Hypertension * Chronic kidney disease stage 1-3 * History of cardiovascular disease with an electrocardiogram available to the physician-investigator through the subject's electronical medical record within the past thirty days showing a normal QT interval (QT \< 500 ms). * History of immunosuppression * Active cancer diagnosis, on palliative treatment or requiring current therapy with antimetabolic agents, immunotherapy or radiotherapy. * At least one fever every 24 hours for \> 72h Exclusion Criteria: * Participation in any other clinical trial of an experimental agent treatment for COVID-19 * Current hospitalization * Known hypersensitivity to hydroxyxhloroquine or chloroquine * Known chronic kidney disease, stage 4-5, or receiving dialysis * History of retinal disease * History of uncontrolled hypertension, defined as systolic blood pressure \> 180 mmHg and or diastolic blood pressure \> 100 mmHg at the most recent physical medical encounter or by patient report. * History of QT prolongation (QT \> 500 ms) or history of Torsades de Pointes * History of arrhythmias * Current use of loop diuretics and potassium supplementation or documented history of hypokalemia. * Pregnancy and lactation * Known glucose-6-phosphate dehydrogenase (G6PD) deficiency * Current use of any of the following medications: flecainide (Tambocor), amiodarone (Cordarone, Pacerone), digoxin (Digox, Digitek), procainamide (Procan, Procanbid), propafenone (Rythmal), antiepileptic agents (phenytoin, phenobarbital, valproic acid, lamotrigine, topiramate), tamoxifen, tricyclic antidepressants (nortriptyline, amitriptyline, imipramine, clomipramine) * Inability to monitor body temperature (oral, axillary, tympanic or frontal) at least twice a day from study enrollment day (Day 1) to the end of the study (Day 14). * Inability to provide informed consent to the study.