1. patient who, in the investigator's opinion, is unlikely to survive\> 48 hours after the inclusion in the study. 2. presence of any of the following abnormal analytical values at the time of the inclusion in the study: * absolute neutrophil count less than 2000 / mm3; * ast or alt\> 5 times the upper limit of normality; * platelets \<50,000 per mm3. 3. patients with respiratory support greater than or equal to 60% 4. in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. 5. known active tuberculosis or known history of tuberculosis uncompleted treatment. 6. patients with active systemic bacterial and / or fungal infections. 7. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). 8. participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. 9. patients who do not have entry criteria in the intensive care unit. 10. pregnancy or lactation. 11. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

1. patient who, in the investigator's opinion, is unlikely to survive\> 48 hours after the inclusion in the study. 2. presence of any of the following abnormal analytical values at the time of the inclusion in the study: * absolute neutrophil count less than 2000 / mm3; * ast or alt\> 5 times the upper limit of normality; * platelets \<50,000 per mm3. 3. patients with respiratory support greater than or equal to 60% 4. in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. 5. known active tuberculosis or known history of tuberculosis uncompleted treatment. 6. patients with active systemic bacterial and / or fungal infections. 7. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). 8. participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. 9. patients who do not have entry criteria in the intensive care unit. 10. pregnancy or lactation. 11. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

patient who, in the investigator's opinion, is unlikely to survive> 48 hours after the inclusion in the study. presence of any of the following abnormal analytical values at the time of the inclusion in the study: absolute neutrophil count less than 2000 / mm3; ast or alt> 5 times the upper limit of normality; platelets <50,000 per mm3. patients with respiratory support greater than or equal to 60% in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. known active tuberculosis or known history of tuberculosis uncompleted treatment. patients with active systemic bacterial and / or fungal infections. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. patients who do not have entry criteria in the intensive care unit. pregnancy or lactation. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

patient who, in the investigator's opinion, is unlikely to survive> 48 hours after the inclusion in the study. presence of any of the following abnormal analytical values at the time of the inclusion in the study: absolute neutrophil count less than 2000 / mm3; ast or alt> 5 times the upper limit of normality; platelets <50,000 per mm3. patients with respiratory support greater than or equal to 60% in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. known active tuberculosis or known history of tuberculosis uncompleted treatment. patients with active systemic bacterial and / or fungal infections. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. patients who do not have entry criteria in the intensive care unit. pregnancy or lactation. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

patient who, in the investigator's opinion, is unlikely to survive> 48 hours after the inclusion in the study. presence of any of the following abnormal analytical values at the time of the inclusion in the study: absolute neutrophil count less than 2000 / mm3; ast or alt> 5 times the upper limit of normality; platelets <50,000 per mm3. in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. known active tuberculosis or known history of tuberculosis uncompleted treatment. patients with active systemic bacterial and / or fungal infections. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. patients who do not have entry criteria in the intensive care unit. pregnancy or lactation. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

patient who, in the investigator's opinion, is unlikely to survive> 48 hours after the inclusion in the study. presence of any of the following abnormal analytical values at the time of the inclusion in the study: absolute neutrophil count less than 2000 / mm3; ast or alt> 5 times the upper limit of normality; platelets <50,000 per mm3. in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. known active tuberculosis or known history of tuberculosis uncompleted treatment. patients with active systemic bacterial and / or fungal infections. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. patients who do not have entry criteria in the intensive care unit. pregnancy or lactation. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

1. patient who, in the investigator's opinion, is unlikely to survive> 48 hours after the inclusion in the study. 2. presence of any of the following abnormal analytical values at the time of the inclusion in the study: - absolute neutrophil count less than 2000 / mm3; - ast or alt> 5 times the upper limit of normality; - platelets <50,000 per mm3. 3. in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. 4. known active tuberculosis or known history of tuberculosis uncompleted treatment. 5. patients with active systemic bacterial and / or fungal infections. 6. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). 7. participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. 8. patients who do not have entry criteria in the intensive care unit. 9. pregnancy or lactation. 10. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).

1. patient who, in the investigator's opinion, is unlikely to survive> 48 hours after the inclusion in the study. 2. presence of any of the following abnormal analytical values at the time of the inclusion in the study: - absolute neutrophil count less than 2000 / mm3; - ast or alt> 5 times the upper limit of normality; - platelets <50,000 per mm3. 3. in active treatment with immunosuppressants or previous prolonged treatment (more 3 months) of oral corticosteroids for a disease not related to covid-19 at a dose greater than 10 mg of prednisone or equivalent per day. 4. known active tuberculosis or known history of tuberculosis uncompleted treatment. 5. patients with active systemic bacterial and / or fungal infections. 6. patients who have received previous treatment with il6 inhibitor (tocilizumab, sarilumab). 7. participants who, at the investigator's discretion, are not eligible to participate, regardless of the reason, including medical or clinical conditions, or participants potentially at risk of not following study procedures. 8. patients who do not have entry criteria in the intensive care unit. 9. pregnancy or lactation. 10. known hypersensitivity to siltuximab or to any of its excipients (histidine, histidine hydrochloride, polysorbate 80 and sucrose).