The investigators aim to evaluate the efficacy of pre-exposure prophylaxis with hydroxychloroquine in healthcare workers with high-risk of SARS-CoV-2 infection.

Inclusion Criteria:

• Age ≥ 18 years
• Negative PCR and negative serology on day 0
• Healthcare worker at any of the trial sites
• Female participants: negative for pregnancy test
• Willing to participate in the study
• Able to sign the informed consent form

Exclusion Criteria:

• Age <18 years

• Pregnancy or breastfeeding

• Ongoing antiviral or antiretroviral treatment or HIV positive

• Ongoing anti-inflammatory treatment (corticosteroids)

• Ongoing or previous (1 month) chloroquine or hydroxychloroquine treatment

• Confirmed case of SARS-CoV-2 infection (positive PCR) at day 0

• Positive serology for SARS-CoV-1 infection at day 0

• Impossibility of signing the informed consent form

• Rejection of participation

• Working less than 3 days a week in the Hospital Clinic of Barcelona.

• Any contraindication for hydroxychloroquine treatment:

  • Hydroxychloroquine hypersensitivity or 4-aminoquinoline hypersensitivity
  • Retinopathy, visual field or visual acuity disturbances
  • QT prolongation, bradycardia (<50bpm), ventricular tachycardia, other arrhythmias, as determined on day 0 ECG or medical history
  • Potassium < 3 mEq/L or AST or ALT > 5 upper normal limit, as determined on day 0 blood test
  • Previous myocardial infarction
  • Myasthenia gravis
  • Porphyria
  • Glomerular clearance < 10ml/min
  • Previous history of severe hypoglycaemia
  • Ongoing treatment with antimalarials, antiarrhythmic, tricyclic antidepressants, selective serotonin reuptake inhibitors, natalizumab, quinolones, macrolides, agalsidase alfa and beta.