Exploratory Study to Evaluate the Efficacy of RUTI® Against SARS-COV-2 Infection (COVID-19) in Healthcare Workers

Inclusion Criteria: 1. Sign the Informed Consent before initiating the selection procedures. 2. Population: 1. Healthcare system workers working in contact with subjects potentially infected with SARS-CoV-2 2. People between 18 years and 59 years 3. Willingness to meet the requirements of the protocol. 4. Negative Rapid Serological Test of SARS-CoV-2 5. The participant must agree to use effective contraceptive methods during the study period, in case of childbearing age. Exclusion Criteria: 1. Previous SARS-CoV-2 infection 2. Pregnancy. Pregnancy test will be performed in case of doubt. 3. Breastfeeding. 4. Suspected of active viral or bacterial infection. 5. Symptoms compatible with COVID-19, despite a negative polymerase chain reaction (PCR) test. 6. Vaccination in the last 4 weeks or planned vaccination during the study period, except for influenza vaccine. 7. Participation in a research that requires experimental intervention (does not include observational studies) in the previous month before signing the Consent or during the study. 8. Severely immunocompromised people. This exclusion category includes: * Subjects with human immunodeficiency virus (HIV-1). * Neutropenic subjects with less than 500 neutrophils / mm3. * Subjects with solid organ transplantation. * Subjects with bone marrow transplantation. * Subjects undergoing chemotherapy. * Subjects with primary immunodeficiency. * Severe lymphopenia with less than 400 lymphocytes / mm3. 9. Malignancy, or active solid or non-solid lymphoma from the previous two years. 10. Soy allergy. 11. Direct involvement in the design or execution of the RUTICOVID19 clinical trial. 12. Retirement, transfer, long-term leave (\> 1 month) due to scheduled surgery or any other event that makes it impossible to work in person at your health center during the months following the recruitment to the study. 13. Do not have a smartphone. 14. Detection by the researcher of lack of knowledge or willingness to participate and comply with all requirements of the protocol. 16\. Any other findings that, at the discretion of the researcher, may compromise compliance with the protocol or that may influence significantly the interpretation or the results of the effects of the vaccine.