* symptom onset \> 14 days; * neutrophil count \< 1,000/mm3; * platelets \< 50,000/mm3; * icu care at enrollment; * on invasive mechanical ventilation at enrollment; * current use of experimental therapy for covid-19 (except: azithromycin or corticosteroids) * uncontrolled arterial hypertension; * current or previous use of systemic immunosuppressive therapy in the last 30 days; * pregnancy or lactation; * estimated creatinine clearance \< 30 ml/min or receiving crrt or intermittent hemodialysis; * allergy to ruxolitinib; * active tuberculosis; * hiv seropositivity; * prior history of progressive multifocal leukoencephalopathy; * use of any jak inhibitor in the last 30 days before study enrollment; * not qualifying according to investigators' perception.

* symptom onset \> 14 days; * neutrophil count \< 1,000/mm3; * platelets \< 50,000/mm3; * icu care at enrollment; * on invasive mechanical ventilation at enrollment; * current use of experimental therapy for covid-19 (except: azithromycin or corticosteroids) * uncontrolled arterial hypertension; * current or previous use of systemic immunosuppressive therapy in the last 30 days; * pregnancy or lactation; * estimated creatinine clearance \< 30 ml/min or receiving crrt or intermittent hemodialysis; * allergy to ruxolitinib; * active tuberculosis; * hiv seropositivity; * prior history of progressive multifocal leukoencephalopathy; * use of any jak inhibitor in the last 30 days before study enrollment; * not qualifying according to investigators' perception.

- symptom onset > 14 days; - neutrophil count < 1,000/mm3; - platelets < 50,000/mm3; - icu care at enrollment; - on invasive mechanical ventilation at enrollment; - current use of experimental therapy for covid-19 (except: azithromycin or corticosteroids) - uncontrolled arterial hypertension; - current or previous use of systemic immunosuppressive therapy in the last 30 days; - pregnancy or lactation; - estimated creatinine clearance < 30 ml/min or receiving crrt or intermittent hemodialysis; - allergy to ruxolitinib; - active tuberculosis; - hiv seropositivity; - prior history of progressive multifocal leukoencephalopathy; - use of any jak inhibitor in the last 30 days before study enrollment; - not qualifying according to investigators' perception.

- symptom onset > 14 days; - neutrophil count < 1,000/mm3; - platelets < 50,000/mm3; - icu care at enrollment; - on invasive mechanical ventilation at enrollment; - current use of experimental therapy for covid-19 (except: azithromycin or corticosteroids) - uncontrolled arterial hypertension; - current or previous use of systemic immunosuppressive therapy in the last 30 days; - pregnancy or lactation; - estimated creatinine clearance < 30 ml/min or receiving crrt or intermittent hemodialysis; - allergy to ruxolitinib; - active tuberculosis; - hiv seropositivity; - prior history of progressive multifocal leukoencephalopathy; - use of any jak inhibitor in the last 30 days before study enrollment; - not qualifying according to investigators' perception.