A Clinical Trial to Evaluate the Efficacy of RUTI® to Reduce the Severity of SARS-CoV-2 Infection (COVID-19)

Once it has been confirmed that the patient meets the selection criteria, subjects will be randomly assigned to one of the two study groups: * Experimental group: Administration of RUTI® * Control group: Administration of Placebo (physiological serum) This randomization follows a 1:1 ratio. In this way, of the total of 550 subjects who intend to be recruited for this study, 275 will receive the prophylactic treatment, and 275 will receive the placebo treatment. Neither patient nor the doctor will know if the subject is part of the experimental group or the control group, that is to say, the treatment assignment is blind. All subjets will receive just one inoculation of treatment (either RUTI® or Pacebo). The standard treatment of COVID-19, if is necessary, will continue after RUTI® administration according to the local guidelines. All the subjets will be followed for one month after the first day of RUTI® or Placebo treatment.