InterLeukin-7 to Improve Clinical Outcomes in Lymphopenic pAtients With COVID-19 Infection FR BL Cohort

Inclusion Criteria: * A written, signed informed consent, or emergency oral consent, by the patient or the patient's legally authorized representative, and the anticipated ability for participant to be re-consented in the future for ongoing Study participation * Men and women aged ≥ 25 - 80 (included) years of age * Hospitalized patients with one absolute lymphocyte count (ALC) ≤ 1000 cells/mm3, collected at baseline or no more than 72h before baseline * Hospitalized patients with moderate to severe hypoxemia requiring oxygen therapy at \>4L per minute nasal cannula or greater to keep saturations \>90%, non-invasive positive pressure ventilation (e.g., BIPAP) for respiratory failure * Confirmed infection with COVID-19 by any acceptable test available/ utilized at each site * Patient with medical insurance or government support Exclusion Criteria: * Pregnancy or breast feeding; * Refusal or inability to practice contraception regardless of the gender of the patient; * ALT and/or AST \> 5 x ULN * Known, active auto-immune disease; * Ongoing cancer treatment with chemotherapy / immunotherapy or any cancer therapy within last 3 months and/or ongoing; * Patients with past history of Solid Organ transplant. * Active tuberculosis, uncontrolled active HBV or HCV infection, HIV with positive viral load. * Patients whose respiratory condition is showing significant deterioration as indicated by: * 8a requirement for an increase in inspired oxygen concentrations of 20% or more over the past 24 hours to maintain SpO2 at greater than or equal to 88% * 8b or need for invasive mechanical ventilation * Patients showing an increase of the NEWS2 score by more than 6 points during the screening / baseline period (48 to 72 hrs prior to first administration) * Patients with chronic kidney dialysis * Patients with a SOFA score ≥ 9 at baseline * Patients with a BMI \> 40 * Patients receiving any agent with immune suppressive effects,such as anti-IL6 treatments like Tocilizumab or Sarilumab which should preferably be minimized * Presence of any of the following abnormal laboratory values at screening: absolute neutrophil count (ANC) \< 1.5x109/L, Platelets \< 50,000 per mm3 * Patients with uncontrolled pre-existing severe major organ dysfunction (cardiac, liver or renal failure) * Vaccination with live attenuated vaccines in the month preceding the inclusion * Use of chronic oral corticosteroids ≥ 10mg prednisone equivalent a day for a non-COVID-19 related condition * Patients with baseline Rockwood Clinical Frailty Scale ≥ 6. * Patients with known hypersensitivity to natural or recombinant Interleukin-7 or to any of the excipients * Patients under guardianship