Identification and Clinical Validation of Biomarkers Associated With Clinical Severity in Adults Infected With RSV

Group of patients with RSV diagnosis Inclusion Criteria: * Age \> 18 years * Positive RSV RT-PCR in nasopharyngeal swab * Patient admitted to the hospital (intensive care unit or medical ward admission at inclusion) with clinical signs of lower respiratory tract infection (defined as the presence of two or more respiratory signes (cough, dyspnea, sputum production, wheezing, tachypnea (respiratory rate\>20/min) or one respiratory sign plus one or more systemic symptoms (fatigue and fever)) requiring hospitalization. * No objection letter (from the patient or a member of family if the patient is not physically able to give consent Exclusion Criteria: * Co-infection with other respiratory viruses * Persons under guardianship/guardianship * AME (state medical aid) patient Group of "control" patients Inclusion Criteria : * Age\>18 years * Patient's consent * Enrolled in a social security plan * Admitted for an acute respiratory syndrome * No diagnosis of respiratory infection in the 4 weeks prior to inclusion * Negative RSV nasopharyngeal PCR (or other respiratory specimen) collected within the last 48 hours * No immunosuppression (HIV infection, bone marrow or solid organ transplantation, post-chemotherapy aplasia, immunosuppressive therapy, corticosteroid therapy (\> 200 mg/d hydrocortisone or equivalent within 4 weeks prior to inclusion) Exclusion Criteria : * Persons under guardianship/guardianship * AME (state medical aid) patient