Safety and Effectiveness Study of Tocilizumab in Patients With Severe COVID-19

Inclusion Criteria: * Hospital admitted patients with severe COVID-19 pneumonia (Individuals who have SpO2 \<94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) \<300 mm Hg, respiratory frequency \>30 breaths/min, or lung infiltrates \>50%). * Confirmed diagnosis of Covid-19 through qualitative polymerase-reverse transcriptase (qRT-PCR -GeneDX Co, Ltd o similar) or antigen rapid test. * Patients who received tocilizumab or shared the same indication but did not received it (same period of time or previous close period) that: * Progress in the requirement of supplemental oxygen (over 3L/m) and/or use of non-rebreathing mask with 8L/m or more to mantain a Sp02\>= 94%. AND \* Active inflammatory state defined as persistent fever \> 38°C (defined as 2 or more measurements in a 24-hour period from hospital admission) despite the use of dexamethasone in the previous 48 hours OR C reactive Protein \> 50 mg /dL OR D Dimer \> 1000 ng/mL. Exclusion Criteria: * Asymptomatic, mild or moderate COVID-19 disease. * Patients with some type of immunosupression (HIV, use of immunomodulatory drugs, organ-trasplant receipt patients) * Pregnant or breast-feeding * Patients with augmented risk of bowel perforation (history of diverticulitis or bowel surgery in the three months prior to the study entrance date) * Known severe allergic reactions to TCZ * Suspected active bacterial, fungal, viral, or other infection (besides COVID-19) * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 5 x upper limit of normal (ULN) at screening * Absolute neutrophil count (ANC) \< 1000/mL at screening * Platelet count \< 50,000/mL at screening * Positive Hepatitis B Surface (HbS) antigen * Procalcitonine \> 0,5 ng/mL * Day of symptom onset before day 7 or after day 12 * Patients with dementia * Patients non eligible to progress to mechanical ventilation because of frailty/comorbidites according to medical decision.