Inclusion Criteria:  Adult Acute symptomatic PCR + COVID with screening Hospitalized for acute COVID between 01/01/2021 (or since the setting up of the screening in the center) and 02/28/2021  Exclusion Criteria:  Opposition to participation Identification of variants other than 20I / 501Y.V1 Patients infected with SARS-CoV-2 in a nosocomial context