* prior receipt of hydroxychloroquine for treatment or prophylaxis of sars-cov-2 or patient is taking hydroxychloroquine for other approved indications (e.g., lupus, rheumatoid arthritis) * no documented sars-cov-2 infection * mechanical ventilation * known hypersensitivity to hydroxychloroquine or 4-aminoquinoline derivatives preexisting retinopathy documented in medical history * pregnancy or breastfeeding * concurrent use of any other quinine derivative (chloroquine, mefloquine) or rifamycins (rifampin, rifabutin) * antiarrhythmic medications (amiodarone, sotalol, dofetilide, procainamide, quinidine, flecainide) * history of glucose-6-phosphate dehydrogenase deficiency * pre-treatment corrected qt interval (qtc) \>500 milliseconds * pressor requirement to maintain blood pressure * alanine aminotransferase (alt) and/or asparate aminotransferase (ast) level \> 5x upper limit of normal * creatinine clearance \<30 ml/min or requirement of dialysis or continuous venovenous hemofiltration * concomitant participation in a therapeutic trial for sars-cov-2 or receiving any experimental treatment for sars-cov-2 within 7 days of randomization * any condition that in the opinion of the principal investigator would prevent participation in the trial or would interfere with the trial endpoints

* prior receipt of hydroxychloroquine for treatment or prophylaxis of sars-cov-2 or patient is taking hydroxychloroquine for other approved indications (e.g., lupus, rheumatoid arthritis) * no documented sars-cov-2 infection * mechanical ventilation * known hypersensitivity to hydroxychloroquine or 4-aminoquinoline derivatives preexisting retinopathy documented in medical history * pregnancy or breastfeeding * concurrent use of any other quinine derivative (chloroquine, mefloquine) or rifamycins (rifampin, rifabutin) * antiarrhythmic medications (amiodarone, sotalol, dofetilide, procainamide, quinidine, flecainide) * history of glucose-6-phosphate dehydrogenase deficiency * pre-treatment corrected qt interval (qtc) \>500 milliseconds * pressor requirement to maintain blood pressure * alanine aminotransferase (alt) and/or asparate aminotransferase (ast) level \> 5x upper limit of normal * creatinine clearance \<30 ml/min or requirement of dialysis or continuous venovenous hemofiltration * concomitant participation in a therapeutic trial for sars-cov-2 or receiving any experimental treatment for sars-cov-2 within 7 days of randomization * any condition that in the opinion of the principal investigator would prevent participation in the trial or would interfere with the trial endpoints

- prior receipt of hydroxychloroquine for treatment or prophylaxis of sars-cov-2 or patient is taking hydroxychloroquine for other approved indications (e.g., lupus, rheumatoid arthritis) - no documented sars-cov-2 infection - mechanical ventilation - known hypersensitivity to hydroxychloroquine or 4-aminoquinoline derivatives preexisting retinopathy documented in medical history - pregnancy or breastfeeding - concurrent use of any other quinine derivative (chloroquine, mefloquine) or rifamycins (rifampin, rifabutin) - antiarrhythmic medications (amiodarone, sotalol, dofetilide, procainamide, quinidine, flecainide) - history of glucose-6-phosphate dehydrogenase deficiency - pre-treatment corrected qt interval (qtc) >500 milliseconds - pressor requirement to maintain blood pressure - alanine aminotransferase (alt) and/or asparate aminotransferase (ast) level > 5x upper limit of normal - creatinine clearance <30 ml/min or requirement of dialysis or continuous venovenous hemofiltration - concomitant participation in a therapeutic trial for sars-cov-2 or receiving any experimental treatment for sars-cov-2 within 7 days of randomization - any condition that in the opinion of the principal investigator would prevent participation in the trial or would interfere with the trial endpoints

- prior receipt of hydroxychloroquine for treatment or prophylaxis of sars-cov-2 or patient is taking hydroxychloroquine for other approved indications (e.g., lupus, rheumatoid arthritis) - no documented sars-cov-2 infection - mechanical ventilation - known hypersensitivity to hydroxychloroquine or 4-aminoquinoline derivatives preexisting retinopathy documented in medical history - pregnancy or breastfeeding - concurrent use of any other quinine derivative (chloroquine, mefloquine) or rifamycins (rifampin, rifabutin) - antiarrhythmic medications (amiodarone, sotalol, dofetilide, procainamide, quinidine, flecainide) - history of glucose-6-phosphate dehydrogenase deficiency - pre-treatment corrected qt interval (qtc) >500 milliseconds - pressor requirement to maintain blood pressure - alanine aminotransferase (alt) and/or asparate aminotransferase (ast) level > 5x upper limit of normal - creatinine clearance <30 ml/min or requirement of dialysis or continuous venovenous hemofiltration - concomitant participation in a therapeutic trial for sars-cov-2 or receiving any experimental treatment for sars-cov-2 within 7 days of randomization - any condition that in the opinion of the principal investigator would prevent participation in the trial or would interfere with the trial endpoints