Clinical Trial of Efficacy, Safety, and Immunogenicity of Gam-COVID-Vac Vaccine Against COVID-19 (RESIST)

Inclusion Criteria:

1. Written informed consent of a subject to participate in the trial
2. Males and females aged ≥18 y.o.;
3. Negative HIV, hepatitis, and syphilis test results
4. Negative anti-SARS CoV2 IgM and IgG antibodies test carried out with the enzyme immunoassay method
5. Negative COVID-2019 PCR test result at the screening visit
6. No COVID-2019 in the past medical history
7. No contact with COVID-2019 diseased 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 past 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 past medical history (ICD codes C00-D09)
9. Donated blood or plasma (450+ ml) within 2 months before the enrollment
10. History of splenectomy;
11. Neutropenia (absolute neutrophil count <1,000/mm3), agranulocytosis, significant blood loss, severe anemia (hemoglobin <80 g/L), immunodeficiency in the past 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 past 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 or other employees directly involved in the trial, or their families.

If a subject has any contraindications to vaccination based on the Guidelines on Detection, Investigation and Prevention, of Vaccination-induced Side Reactions (approved by the Ministry of Healthcare of Russia on Apr. 12, 2019, the vaccination may be postponed for a period of time specified in the document.