Dexamethasone associated with hydroxychloroquine vs. hydroxychloroquine alone for the early treatment of severe ARDS caused by COVID-19 : a randomized controlled trial

Inclusion criteria: 1. Patient aged > 18 2. Patient affiliated to a health insurance plan 3. Patient who has given their free, informed and written consent or patient for whom an independent doctor has given their signed consent as part of an emergency procedure 4. Serum Potassium> 3,5 mmol / L 5. Patient diagnosed COVID positive by RT-PCR and / or scanner Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18-64 years) yes F.1.2.1 Number of subjects for this age range 80 F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range 42 Main Objective: Assess, in patients with ARDS caused by COVID-19, the efficacy of dexamethasone (DXM) associated with hydroxychloroquine (HCQ) compared to HCQ alone on mortality at 28 days Secondary Objective: Assess, in patients with ARDS causedd by COVID-19, the efficacy of DXM associated with HCQ compared to HCQ alone on : - the ventilator-free days - mortality in intensive care unit - mortality on D60 - the occurrence of infectious complications Primary end point(s): Mortality on D28 ;Timepoint(s) of evaluation of this end point: the 28th day after the start of treatment