1. greater than 96 hours since last exposure 2. presence of fever (t\>37.8), new onset cough, or shortness of breath at enrollment 3. a baseline o2 saturation less than 90% (as measured by pulse oximetry) on room air 4. screening ecg qtc interval greater than 500ms by either a 12 lead or 6 lead ecg. 5. concomitant drug-drug interactions (artemether, dapsone, lumefantrine or mefloquine amiodarone, digoxin, dofetilide, flecainide, procainamide, sotalol, or propafenone levofloxacin, ciprofloxacin, moxifloxacin, azithromycin, clarithromycin, erythromycin, ketoconazole, or itraconazole methadone sumatriptan, or zolmitriptan systemic chemotherapy.) 6. already on active palliative care measures (palliative performance score (pps) less than 30%) 7. hypersensitivity reaction to chloroquine, hydroxychloroquine or aminoquinolines 8. history of retinal disease due to previous use of 4-aminoquinoline 9. prior documented and known at enrollment, retinal eye disease or maculopathy including but not limited to diabetic retinopathy, retinal detachment, retinitis pigmentosa or macular degeneration 10. known glucose-6 phosphate dehydrogenase (g6pd) deficiency 11. known porphyria 12. acute delirium 13. inability to swallow oral study drug/placebo (even after crushed in the same manner as regular prescribed medications) 14. diagnosis of immunodeficiency (e.g. hiv, transplantation) or receiving systemic steroid therapy (\>10mg prednisone daily or equivalent) or any other form of immunosuppressive therapy prior to trial treatment 15. women who are pregnant or breastfeeding

1. greater than 96 hours since last exposure 2. presence of fever (t\>37.8), new onset cough, or shortness of breath at enrollment 3. a baseline o2 saturation less than 90% (as measured by pulse oximetry) on room air 4. screening ecg qtc interval greater than 500ms by either a 12 lead or 6 lead ecg. 5. concomitant drug-drug interactions (artemether, dapsone, lumefantrine or mefloquine amiodarone, digoxin, dofetilide, flecainide, procainamide, sotalol, or propafenone levofloxacin, ciprofloxacin, moxifloxacin, azithromycin, clarithromycin, erythromycin, ketoconazole, or itraconazole methadone sumatriptan, or zolmitriptan systemic chemotherapy.) 6. already on active palliative care measures (palliative performance score (pps) less than 30%) 7. hypersensitivity reaction to chloroquine, hydroxychloroquine or aminoquinolines 8. history of retinal disease due to previous use of 4-aminoquinoline 9. prior documented and known at enrollment, retinal eye disease or maculopathy including but not limited to diabetic retinopathy, retinal detachment, retinitis pigmentosa or macular degeneration 10. known glucose-6 phosphate dehydrogenase (g6pd) deficiency 11. known porphyria 12. acute delirium 13. inability to swallow oral study drug/placebo (even after crushed in the same manner as regular prescribed medications) 14. diagnosis of immunodeficiency (e.g. hiv, transplantation) or receiving systemic steroid therapy (\>10mg prednisone daily or equivalent) or any other form of immunosuppressive therapy prior to trial treatment 15. women who are pregnant or breastfeeding

greater than 96 hours since last exposure presence of fever (t>37.8), new onset cough, or shortness of breath at enrollment a baseline o2 saturation less than 90% (as measured by pulse oximetry) on room air screening ecg qtc interval greater than 500ms by either a 12 lead or 6 lead ecg. concomitant drug-drug interactions (artemether, dapsone, lumefantrine or mefloquine amiodarone, digoxin, dofetilide, flecainide, procainamide, sotalol, or propafenone levofloxacin, ciprofloxacin, moxifloxacin, azithromycin, clarithromycin, erythromycin, ketoconazole, or itraconazole methadone sumatriptan, or zolmitriptan systemic chemotherapy.) already on active palliative care measures (palliative performance score (pps) less than 30%) hypersensitivity reaction to chloroquine, hydroxychloroquine or aminoquinolines history of retinal disease due to previous use of 4-aminoquinoline prior documented and known at enrollment, retinal eye disease or maculopathy including but not limited to diabetic retinopathy, retinal detachment, retinitis pigmentosa or macular degeneration known glucose-6 phosphate dehydrogenase (g6pd) deficiency known porphyria acute delirium inability to swallow oral study drug/placebo (even after crushed in the same manner as regular prescribed medications) diagnosis of immunodeficiency (e.g. hiv, transplantation) or receiving systemic steroid therapy (>10mg prednisone daily or equivalent) or any other form of immunosuppressive therapy prior to trial treatment women who are pregnant or breastfeeding

greater than 96 hours since last exposure presence of fever (t>37.8), new onset cough, or shortness of breath at enrollment a baseline o2 saturation less than 90% (as measured by pulse oximetry) on room air screening ecg qtc interval greater than 500ms by either a 12 lead or 6 lead ecg. concomitant drug-drug interactions (artemether, dapsone, lumefantrine or mefloquine amiodarone, digoxin, dofetilide, flecainide, procainamide, sotalol, or propafenone levofloxacin, ciprofloxacin, moxifloxacin, azithromycin, clarithromycin, erythromycin, ketoconazole, or itraconazole methadone sumatriptan, or zolmitriptan systemic chemotherapy.) already on active palliative care measures (palliative performance score (pps) less than 30%) hypersensitivity reaction to chloroquine, hydroxychloroquine or aminoquinolines history of retinal disease due to previous use of 4-aminoquinoline prior documented and known at enrollment, retinal eye disease or maculopathy including but not limited to diabetic retinopathy, retinal detachment, retinitis pigmentosa or macular degeneration known glucose-6 phosphate dehydrogenase (g6pd) deficiency known porphyria acute delirium inability to swallow oral study drug/placebo (even after crushed in the same manner as regular prescribed medications) diagnosis of immunodeficiency (e.g. hiv, transplantation) or receiving systemic steroid therapy (>10mg prednisone daily or equivalent) or any other form of immunosuppressive therapy prior to trial treatment women who are pregnant or breastfeeding

1. greater than 96 hours since last exposure 2. presence of fever (t>37.8), new onset cough, or shortness of breath at enrollment 3. a baseline o2 saturation less than 90% (as measured by pulse oximetry) on room air 4. screening ecg qtc interval greater than 500ms by either a 12 lead or 6 lead ecg. 5. concomitant drug-drug interactions (artemether, dapsone, lumefantrine or mefloquine amiodarone, digoxin, dofetilide, flecainide, procainamide, sotalol, or propafenone levofloxacin, ciprofloxacin, moxifloxacin, azithromycin, clarithromycin, erythromycin, ketoconazole, or itraconazole methadone sumatriptan, or zolmitriptan systemic chemotherapy.) 6. already on active palliative care measures (palliative performance score (pps) less than 30%) 7. hypersensitivity reaction to chloroquine, hydroxychloroquine or aminoquinolines 8. history of retinal disease due to previous use of 4-aminoquinoline 9. prior documented and known at enrollment, retinal eye disease or maculopathy including but not limited to diabetic retinopathy, retinal detachment, retinitis pigmentosa or macular degeneration 10. known glucose-6 phosphate dehydrogenase (g6pd) deficiency 11. known porphyria 12. acute delirium 13. inability to swallow oral study drug/placebo (even after crushed in the same manner as regular prescribed medications) 14. diagnosis of immunodeficiency (e.g. hiv, transplantation) or receiving systemic steroid therapy (>10mg prednisone daily or equivalent) or any other form of immunosuppressive therapy prior to trial treatment 15. women who are pregnant or breastfeeding

1. greater than 96 hours since last exposure 2. presence of fever (t>37.8), new onset cough, or shortness of breath at enrollment 3. a baseline o2 saturation less than 90% (as measured by pulse oximetry) on room air 4. screening ecg qtc interval greater than 500ms by either a 12 lead or 6 lead ecg. 5. concomitant drug-drug interactions (artemether, dapsone, lumefantrine or mefloquine amiodarone, digoxin, dofetilide, flecainide, procainamide, sotalol, or propafenone levofloxacin, ciprofloxacin, moxifloxacin, azithromycin, clarithromycin, erythromycin, ketoconazole, or itraconazole methadone sumatriptan, or zolmitriptan systemic chemotherapy.) 6. already on active palliative care measures (palliative performance score (pps) less than 30%) 7. hypersensitivity reaction to chloroquine, hydroxychloroquine or aminoquinolines 8. history of retinal disease due to previous use of 4-aminoquinoline 9. prior documented and known at enrollment, retinal eye disease or maculopathy including but not limited to diabetic retinopathy, retinal detachment, retinitis pigmentosa or macular degeneration 10. known glucose-6 phosphate dehydrogenase (g6pd) deficiency 11. known porphyria 12. acute delirium 13. inability to swallow oral study drug/placebo (even after crushed in the same manner as regular prescribed medications) 14. diagnosis of immunodeficiency (e.g. hiv, transplantation) or receiving systemic steroid therapy (>10mg prednisone daily or equivalent) or any other form of immunosuppressive therapy prior to trial treatment 15. women who are pregnant or breastfeeding