Clinical Trial of the Immunogenicity, Safety, and Efficacy of the Gam-COVID-Vac Vaccine Against COVID-19 in Venezuela

Inclusion Criteria: 1. Written informed consent of a subject to participate in the trial 2. Males and females aged 18+ 3. Negative HIV, hepatitis, and syphilis test results 4. A negative test result for the presence of IgM and IgG antibodies to SARS CoV2 by enzyme immunoassay 5. A negative test result for COVID-2019 by PCR at screening visit 6. No COVID-2019 in the medical history 7. No contact with COVID-2019 persons within at least 14 days before the enrollment (according to trial subjects) 8. Consent to use effective contraception methods during the trial 9. Negative urine pregnancy test at the screening visit (for child-bearing age women) 10. Negative drugs or psychostimulants urine test at the screening visit 11. Negative alcohol test at the screening visit 12. No evident vaccine-induced reactions or complications after receiving immunobiological products in the medical history 13. No acute infectious and/or respiratory diseases within at least 14 days before the enrollment. Exclusion Criteria: 1. Any vaccination/immunization within 30 days before the enrollment; 2. Steroids (except hormonal contraceptives) and/or immunoglobulins or other blood products therapy not finished 30 days before the enrollment. 3. Immunosuppressors therapy finished within 3 months before the enrollment 4. Pregnancy or breast-feeding 5. Acute coronary syndrome or stroke suffered less than one year before the enrollment 6. Tuberculosis, chronic systemic infections 7. Drug allergy (anaphylactic shock, Quincke's edema, polymorphic exudative eczema, atopy, serum disease), hypersensitivity or allergic reaction to immunobiological products, known allergic reactions to study drug components, acute exacerbation of allergic diseases on the enrollment day 8. Neoplasms in the medical history. 9. Donated blood or plasma (450+ ml) within 2 months before the enrollment 10. Splenectomy in the medical history 11. Neutropenia (absolute neutrophil count \<1,000 mm3), agranulocytosis, significant blood loss, severe anemia (hemoglobin \<80 g/L), immunodeficiency in the medical history within 6 months before the enrollment 12. Active form of a disease caused by the human immunodeficiency virus, syphilis, hepatitis B or C 13. Anorexia, protein deficiency of any origin 14. Big-size tattoos at the injection site (deltoid muscle area), which does not allow assessing the local response to the study drug/placebo administration 15. Alcohol or drug addiction in the medical history 16. Participation in any other interventional clinical trial. 17. Any other condition that the study physician considers as a barrier to the trial completion as per the protocol 18. Study center staff and other employees directly involved in the trial and their families.