- previous positive test for sars-cov-2 - previous positive serology test for sars-cov-2 - recent chest ct meeting ct exclusion criteria - live in a skilled nursing facility with covid-19 symptoms (temp >38 c in addition to sore throat, cough, wheezing, chest tightness, shortness of breath, body aches or chills, diarrhea, anosmia) - known hypersensitivity to hydroxychloroquine or 4-aminoquinoline derivatives - pre-existing retinopathy - known chronic kidney disease, stage 4 or 5, or receiving dialysis - breast feeding - tamoxifen - absolute neutrophil count <1,000/ml at registration - concurrent use of any other quinine derivative - antiarrhythmic medications: amiodarone, sotalol, dofetilide, procainamide, quinidine, flecainide - glucose-6-phosphate dehydrogenase deficiency - pre-treatment corrected qt interval (qtc) ≥470 milliseconds** - prisoners - inability to participate - psoriasis - history of suicidal ideation - ct criteria for enrollment exclusion (optional - only for patients who received a diagnostic ct as part of standard of care or a thoracic ct as part of radiation simulation): all patients with covid-19 typical radiographic findings on ct chest as defined by the rsna will be excluded. patients with any new covid-19 indeterminate radiographic findings on ct chest that are concerning for covid-19 will be excluded. covid-19 indeterminate features are permitted if they can be demonstrated as stable on prior (>14 calendar days) ct chest or pet/ct. if no prior comparison is available and any intermediate or typical feature is present, the patient is not eligible. - covid-19 atypical features - isolated lobar or segmental consolidation without ggo - discrete small nodules (centrilobular, "tree-in-bud") - lung cavitation - smooth interlobular septal thickening with pleural effusion - covid-19 indeterminate features - multifocal, diffuse, perihilar, or unilateral ggo with or without consolidation lacking a specific distribution and are non-rounded or non-peripheral - few very small ggo with a non-rounded and non-peripheral distribution - covid-19 typical features - peripheral, bilateral ggo with or without consolidation or visible intralobular lines ("crazy paving") - multifocal ggo of rounded morphology with or without consolidation or visible intralobular lines ("crazy paving") - reverse halo sign or other findings of organizing pneumonia ** if pre-treatment qtc can be decreased to <470, the patient can be re-considered for trial.

- previous positive test for sars-cov-2 - previous positive serology test for sars-cov-2 - recent chest ct meeting ct exclusion criteria - live in a skilled nursing facility with covid-19 symptoms (temp >38 c in addition to sore throat, cough, wheezing, chest tightness, shortness of breath, body aches or chills, diarrhea, anosmia) - known hypersensitivity to hydroxychloroquine or 4-aminoquinoline derivatives - pre-existing retinopathy - known chronic kidney disease, stage 4 or 5, or receiving dialysis - breast feeding - tamoxifen - absolute neutrophil count <1,000/ml at registration - concurrent use of any other quinine derivative - antiarrhythmic medications: amiodarone, sotalol, dofetilide, procainamide, quinidine, flecainide - glucose-6-phosphate dehydrogenase deficiency - pre-treatment corrected qt interval (qtc) ≥470 milliseconds** - prisoners - inability to participate - psoriasis - history of suicidal ideation - ct criteria for enrollment exclusion (optional - only for patients who received a diagnostic ct as part of standard of care or a thoracic ct as part of radiation simulation): all patients with covid-19 typical radiographic findings on ct chest as defined by the rsna will be excluded. patients with any new covid-19 indeterminate radiographic findings on ct chest that are concerning for covid-19 will be excluded. covid-19 indeterminate features are permitted if they can be demonstrated as stable on prior (>14 calendar days) ct chest or pet/ct. if no prior comparison is available and any intermediate or typical feature is present, the patient is not eligible. - covid-19 atypical features - isolated lobar or segmental consolidation without ggo - discrete small nodules (centrilobular, "tree-in-bud") - lung cavitation - smooth interlobular septal thickening with pleural effusion - covid-19 indeterminate features - multifocal, diffuse, perihilar, or unilateral ggo with or without consolidation lacking a specific distribution and are non-rounded or non-peripheral - few very small ggo with a non-rounded and non-peripheral distribution - covid-19 typical features - peripheral, bilateral ggo with or without consolidation or visible intralobular lines ("crazy paving") - multifocal ggo of rounded morphology with or without consolidation or visible intralobular lines ("crazy paving") - reverse halo sign or other findings of organizing pneumonia ** if pre-treatment qtc can be decreased to <470, the patient can be re-considered for trial.