* 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

* 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

- 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

- 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

- 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. - hospitalized patients with refractory hypoxia, defined as inability to maintain saturation >85% with maximal available therapy for >6 hours - patients receiving any agent with immune suppressive effects, other than steroids at dosages less than 300 mg/day and/or 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

- 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. - hospitalized patients with refractory hypoxia, defined as inability to maintain saturation >85% with maximal available therapy for >6 hours - patients receiving any agent with immune suppressive effects, other than steroids at dosages less than 300 mg/day and/or 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