Clinical Trial of the Use of Tocilizumab for Treatment of SARS-CoV-2 Infection (COVID-19)

Inclusion Criteria: * Subject (or authorized legal representative) who can provide written informed consent before beginning any study procedure. * Understand and agree to abide by the study procedures. * Adult #18 years of age at the time of inclusion in the study. * Confirmation of SARS-CoV-2 infection by a microbiological test performed before randomization, no longer than 72 hours. * Severity 3-4 according to the WHO 7-point ordinal scale. Exclusion Criteria: * ALT / AST\> 5 times the normal limit * Stage 4 chronic kidney disease (GFR \<30) or requiring dialysis. * Presence of comorbidities that imply a poor prognosis (according to clinical judgment). * Advanced dementia. * Pregnancy or breastfeeding. * Anticipation of transfer to another center in the 12 hours at the beginning of the study. * Allergy to study medication. * Serious or active bacterial infections or documented sepsis by pathogens other than SARS-CoV-2. * Streptococcus pneumoniae antigenuria positive before study start. * Neutropenia \<500 / mm3. * Thrombocytopenia \<100,000 / mm3. * History of diverticulosis. * Ongoing skin infection (eg, pyodermitis). * Transplanted patient under immunosuppressive treatment. * Previous evidence of latent untreated tuberculosis.