This a double-blind, randomized, placebo-controlled clinical trial to determine if primary prophylaxis with hydroxychloroquine in healthcare workers reduces symptomatic COVID-19 infection. Healthcare workers will be randomized at a 1:1 allocation between intervention and placebo arms and followed for 12 weeks. This study will enroll up to 1,700 participates in Lafayette, Louisiana. The primary outcome will number of symptomatic COVID-19 infections. Secondary endpoints included number of days healthcare workers are absent from work and rate of severe infection.

The study is a double blind placebo controlled at two hospitals in Lafayette, Louisiana aiming to enroll 1700 participants with a 1:1 randomization. The HCQ dose in 400mg twice on day 1, then 200mg twice weekly. The primary outcome variable is development of symptomatic COVID-19 infection. The secondary objectives are number of days absent from work due to symptomatic COVID-19 infection and rate of severe disease due to COVID-19 (hypoxia in setting of >50% lung involvement on chest imaging, respiratory failure, shock or end-organ damage). The study will enroll participants for four weeks with and plan to treat with hydroxychloroquine versus placebo for a total of 12 weeks.

Inclusion Criteria:

1. Age ≥ 18 years
2. Healthcare or Hospital Worker who has direct patient contact
3. Willing to participate in the research.
4. Able to understand and sign the informed consent form

Exclusion Criteria:

1. Age < 18 years
2. History of ventricular arrhythmia or use of Class IA, IC and III anti-arrhythmics
3. Known prolonged QTc interval
4. History of retinal disease
5. Kidney failure with GFR <10%
6. Chronic hepatic disease w/ Child-Pugh class B or C
7. Hypersensitivity to chloroquine or hydroxychloroquine
8. Currently taking chloroquine or hydroxychloroquine
9. Unwilling to participate
10. Unable to understand and/or sign the informed consent form.

Participants will be randomized to the investigational drug (hydroxychloroquine) or placebo. Both will have identical appearance and will be taken at the same dosing interval. The administration of the drug and assessment will be blinded. After final analysis, study arms will be unmasked.