Phase 2B: Reduction of SARS-CoV2 viral load assessed by Ct PCR at day-4 adjusted on Ct PCR SARS-CoV2 viral load at baseline (ANCOVA);Phase 3: Rate of non-contagious nasopharyngeal sample for SARS-CoV2 by PCR on Day-4 with Ct > or = 28

Phase 2B: Reduction of SARS-CoV2 viral load assessed by Ct PCR at day-4 adjusted on Ct PCR SARS-CoV2 viral load at baseline (ANCOVA);Phase 3: Rate of non-contagious nasopharyngeal sample for SARS-CoV2 by PCR on Day-4 with Ct > or = 28