Comparative assessment of the tolerability, safety, and immunogenicity of the Flu-M® Inactivated Split Influenza Vaccine (without preservative) and the Flu-M® vaccine (with preservative) in volunteers aged between 18 and 60

1. Assessment of the tolerability and safety of the Flu-M® inactivated split influenza vaccine (without preservative) and Flu-M® (with preservative).
2. Assessment of the immunogenicity of the Flu-M® inactivated split influenza vaccine (with preservative) and Flu-M® (without preservative).

Single administration of the trial products. Duration of follow-up - 28+3 (outpatient visit) and Long-term follow-up - 180±3 days.

Inclusion Criteria:

1. Healthy volunteers (men and women) aged 18-60 years;
2. Written informed consent of volunteers to participate in the clinical trial;
3. Volunteers able to fulfill requirements of the Protocol (i.e. fill out the patient's diary, come to follow-up visits);
4. For fertile women - a negative result of the pregnancy test and consent to observe adequate methods of contraception during the trial and at least two months after vaccination
5. For fertile men - consent to observe adequate methods of contraception during the trial and at least two months after vaccination, except for men after vasectomy with documented azoospermia, and their sexual partners should use methods of contraception that ensure more than 90% reliability or be incapable of conception after a surgical sterilization or have a natural menopause for at least 2 years.

Exclusion Criteria:

1. History of influenza/ARVI or previous influenza vaccination during 6 months before the trial;
2. Positive result of the SARS-CoV-2 test;
3. A serious post-vaccination reaction (temperature above 40 °C, hyperemia or edema more than 8 cm in diameter) or complications (collapse or shock-like condition that developed within 48 hours after vaccination; convulsions accompanied or not accompanied by a fever due to any previous vaccination);
4. Allergic reactions to vaccine components or any previous vaccination;
5. History of allergic reaction to chicken protein;
6. Guillain-Barré syndrome (acute polyneuropathy) in the medical history;
7. Previous vaccination with rabies vaccines less than 2 months before immunization or scheduled vaccination with rabies vaccines within 1 month after immunization with the trial vaccines;
8. Use of any vaccines within 1 month before the vaccination, excluding vaccines according to the National Calendar of Preventive Vaccination, including for epidemic reasons;
9. History of leukemia, cancer, autoimmune diseases;
10. (Positive blood test results for HIV, syphilis, hepatitis B/C;
11. Volunteers who received immunoglobulin or blood products or had a blood transfusion during the last three months before the trial;
12. History of long-term use (more than 14 days) of immunosuppressants or immunomodulatory drugs for six months before the trial;
13. History of any confirmed or suspected immunosuppressive or immunodeficiency condition;
14. History of chronic diseases of the cardiovascular, bronchopulmonary, neuroendocrine systems, the gastrointestinal tract, liver, kidneys, hematopoietic or immune systems, mental disease in the acute stage or in the decompensation stage (recovery less than 4 weeks before vaccination);
15. Diabetes mellitus, thyrotoxicosis or other diseases of the endocrine system;
16. History of eczema;
17. Treatment with glucocorticosteroids, including in small doses, as well as local use of drugs containing steroids (> 10 mg of prednisolone or its equivalent for more than 14 days before the screening);
18. Tuberculosis, neurological or mental disorders, a convulsive syndrome, including in the past medical history;
19. History of acute infectious diseases (recovery less than 4 weeks before vaccination);
20. Consumption of more than 10 units of alcohol per week or history of alcohol addiction, drug addiction or abuse of pharmaceutical products;
21. Smoking of more than 10 cigarettes per day;
22. Participation in another clinical trial during the last 3 months;
23. Pregnancy or lactation;
24. Coagulopathy, including hemophilia;
25. Taking aspirin or other antiplatelet agents in high doses.