1. known g6pd deficiency 2. contra-indication to hydroxychloroquine, azithromycin or vitamin c: allergy to study interventions, epilepsy, serious hearing or visual problems, history of severe depression, calcium oxalate stones, advanced liver disease, pregnancy or lactating 3. already receiving chloroquine, azithromycin, \>3 grams vitamin c daily or an experimental antiviral 4. history of fever (e.g. night sweats, chills) and/or acute respiratory infection (e.g. cough, shortness of breath, sore throat) of more than 7 days' duration. note, if study numbers not quickly reached, the investigators may decide to include those with symptoms of longer than 7 days 5. calculated creatinine clearance of \< 30 ml/minute 6. baseline ecg showing: qtc ≥470 for males, qtc ≥480 for females 7. receipt of a drug known to increase qtc: quetiapine, amiodarone, sotalol

1. known g6pd deficiency 2. contra-indication to hydroxychloroquine, azithromycin or vitamin c: allergy to study interventions, epilepsy, serious hearing or visual problems, history of severe depression, calcium oxalate stones, advanced liver disease, pregnancy or lactating 3. already receiving chloroquine, azithromycin, \>3 grams vitamin c daily or an experimental antiviral 4. history of fever (e.g. night sweats, chills) and/or acute respiratory infection (e.g. cough, shortness of breath, sore throat) of more than 7 days' duration. note, if study numbers not quickly reached, the investigators may decide to include those with symptoms of longer than 7 days 5. calculated creatinine clearance of \< 30 ml/minute 6. baseline ecg showing: qtc ≥470 for males, qtc ≥480 for females 7. receipt of a drug known to increase qtc: quetiapine, amiodarone, sotalol

known g6pd deficiency contra-indication to hydroxychloroquine, azithromycin or vitamin c: allergy to study interventions, epilepsy, serious hearing or visual problems, history of severe depression, calcium oxalate stones, advanced liver disease, pregnancy or lactating already receiving chloroquine, azithromycin, >3 grams vitamin c daily or an experimental antiviral history of fever (e.g. night sweats, chills) and/or acute respiratory infection (e.g. cough, shortness of breath, sore throat) of more than 7 days' duration. note, if study numbers not quickly reached, the investigators may decide to include those with symptoms of longer than 7 days calculated creatinine clearance of < 30 ml/minute baseline ecg showing: qtc ≥470 for males, qtc ≥480 for females receipt of a drug known to increase qtc: quetiapine, amiodarone, sotalol

known g6pd deficiency contra-indication to hydroxychloroquine, azithromycin or vitamin c: allergy to study interventions, epilepsy, serious hearing or visual problems, history of severe depression, calcium oxalate stones, advanced liver disease, pregnancy or lactating already receiving chloroquine, azithromycin, >3 grams vitamin c daily or an experimental antiviral history of fever (e.g. night sweats, chills) and/or acute respiratory infection (e.g. cough, shortness of breath, sore throat) of more than 7 days' duration. note, if study numbers not quickly reached, the investigators may decide to include those with symptoms of longer than 7 days calculated creatinine clearance of < 30 ml/minute baseline ecg showing: qtc ≥470 for males, qtc ≥480 for females receipt of a drug known to increase qtc: quetiapine, amiodarone, sotalol

1. known g6pd deficiency 2. contra-indication to hydroxychloroquine, azithromycin or vitamin c: allergy to study interventions, epilepsy, serious hearing or visual problems, history of severe depression, calcium oxalate stones, advanced liver disease, pregnancy or lactating 3. already receiving chloroquine, azithromycin, >3 grams vitamin c daily or an experimental antiviral 4. history of fever (e.g. night sweats, chills) and/or acute respiratory infection (e.g. cough, shortness of breath, sore throat) of more than 7 days' duration. note, if study numbers not quickly reached, the investigators may decide to include those with symptoms of longer than 7 days 5. calculated creatinine clearance of < 30 ml/minute 6. baseline ecg showing: qtc ≥470 for males, qtc ≥480 for females 7. receipt of a drug known to increase qtc: quetiapine, amiodarone, sotalol

1. known g6pd deficiency 2. contra-indication to hydroxychloroquine, azithromycin or vitamin c: allergy to study interventions, epilepsy, serious hearing or visual problems, history of severe depression, calcium oxalate stones, advanced liver disease, pregnancy or lactating 3. already receiving chloroquine, azithromycin, >3 grams vitamin c daily or an experimental antiviral 4. history of fever (e.g. night sweats, chills) and/or acute respiratory infection (e.g. cough, shortness of breath, sore throat) of more than 7 days' duration. note, if study numbers not quickly reached, the investigators may decide to include those with symptoms of longer than 7 days 5. calculated creatinine clearance of < 30 ml/minute 6. baseline ecg showing: qtc ≥470 for males, qtc ≥480 for females 7. receipt of a drug known to increase qtc: quetiapine, amiodarone, sotalol