- Need of hospitalization before or at enrollment visit (visit 1) - Known contra-indication to HC (hypersensitivity to 4-aminoquinoline compounds, ocular retinopathy, epilepsy, diabetes) - Pregnancy or breast-feeding - Use of any other (experimental) drug aiming to treat COVID-19 - Use of any treatment with potential interaction with HC and flagged “red” or “orange” in the list of drug interactions published on the reference website http://www.covid19-druginteractions.org/ (accessed on 30/03/2020). This is a dynamic list which is being updated as new information becomes available. The most recent update of the list will be used. Antacids are flagged orange but can be used if taken at least 4h before or 4h after HC.

- Need of hospitalization before or at enrollment visit (visit 1) - Known contra-indication to HC (hypersensitivity to 4-aminoquinoline compounds, ocular retinopathy, epilepsy, diabetes) - Pregnancy or breast-feeding - Use of any other (experimental) drug aiming to treat COVID-19 - Use of any treatment with potential interaction with HC and flagged “red” or “orange” in the list of drug interactions published on the reference website http://www.covid19-druginteractions.org/ (accessed on 30/03/2020). This is a dynamic list which is being updated as new information becomes available. The most recent update of the list will be used. Antacids are flagged orange but can be used if taken at least 4h before or 4h after HC.