Hydroxychloroquine to Prevent SARS-CoV-2 Infection/COVID-19

Inclusion Criteria: 1. Healthcare workers in service during the COVID-19 outbreak including medical, nurse, technical, and auxiliary staff. 2. Negative rapid serologic and molecular testing for SARS-CoV-2. 3. Written informed consent. Exclusion Criteria: 1. Presents COVID-19 symptoms including cough, fever, myalgias, headaches, loss of smell, and taste. 2. Prior (last 30 days), current or planned use (during study period) of hydroxychloroquine, chloroquine sulfate, or azithromycin. 3. Known cardiac disease or a history of prolonged QT syndrome. 4. Known allergy or intolerance to hydroxychloroquine and/or chloroquine sulfate. 5. Use of concomitant medications that are contraindicated with the use of hydroxychloroquine. 6. Other reported medical conditions, such as glucose-6-phosphate dehydrogenase deficiency, hepatic or renal insufficiency, or visual acuity or field disturbances, that make study participation not in the individual's best interest.