Chemoprophylaxis of SARS-CoV-2 Infection (COVID-19) in Exposed Healthcare Workers

The study COVIDAXIS 1(Hydroxychloroquine (HCQ) versus placebo) will be realized on 600 participants and will be implemented first in as many centers as possible. Upon randomization, with 1:1 allocation ratio, healthcare workers involved in the management of suspected or confirmed COVID-19 cases will be assigned to one of the following 2 treatment groups: * Group 1.1: HCQ 200 mg : 2 tablets on the evening at Day 1 and 2 tablets on the morning at Day 2 and 1 tablet once daily afterwards * Group 1.2: Placebo of HCQ, 2 tablets on the evening at Day 1 and 2 tablets on the morning at Day 2 and 1 tablet once daily afterwards. The COVIDAXIS 2 (Lopinavir/ritonavir (LPV/r) versus placebo will be realized on 600 participants and will be implemented in already participating and newer centers in a second step (when LPV/r becomes available). Upon randomization, with 1:1 allocation ratio, healthcare workers involved in the management of suspected or confirmed COVID-19 cases will be assigned to one of the following 2 treatment groups: * Group 2.1: LPV/r 200/50 mg : 2 tablets twice daily * Group 2.2: Placebo of LPV/r, 2 tablets twice daily Participants will receive the randomized treatment for 2 months and will be followed upon a 2.5 months period. NB: there is no randomization procedure for participant inclusion in either COVIDAXIS 1 or COVIDAXIS 2