The goal of this clinical trial is to assess tolerability, safety and immunogenicity of the Flu-M Quadro vaccine as compared to the Ultrix® Quadri vaccine in volunteers aged between 18 and 60.

Participants were given Flu-M Quadro [inactivated split influenza vaccine] with preservative or Flu-M Quadro [inactivated split influenza vaccine] without preservative or Ultrix® Quadri vaccine.The volunteers of each group were vaccinated with a single dose vaccine.

Researchers assessed the tolerability, safety and immunogenicity of the Flu-M Quadro quadrivalent inactivated split influenza vaccine.

Researchers performed a comparative assessment of the tolerability, safety, and immunogenicity of the Flu-M Quadro quadrivalent inactivated split influenza vaccine and the Ultrix® Quadri vaccine.

Inclusion Criteria:

• Healthy volunteers (men and women) aged 18-60;
• Written informed consent of the volunteers to participate in the clinical trial;
• Volunteers able to fulfill requirements of the protocol (i.e., fill out the patient's diary, come to follow-up visits);
• For fertile women - a negative result of the pregnancy test and consent to observe adequate methods of contraception (usage of contraceptives one month before vaccination and at least two months after vaccination). All females with childbearing potential must have a negative pregnancy test result during the screening period. In the course of the trial women should use barrier contraceptives with a reliability exceeding 90 %, or be sterile, or be in a postmenopausal state. Barrier contraceptives with a reliability exceeding 90 % of common use include cervical caps with spermicide, diaphragms with spermicide, condoms, intra-uterine spirals;
• For the men, are able to conceive - consent to use adequate contraception methods. In the course of the trial and during at least two months after vaccination, men and their sexual partners should use barrier contraceptives with a reliability exceeding 90 %, or be sterile. Barrier contraceptives with a reliability exceeding 90 % of common use include cervical caps with spermicide, diaphragms with spermicide, condoms, intra-uterine spirals;

Exclusion Criteria:

• History of influenza or ARVI or previous influenza vaccination during 9 moths before the trial;
• 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);
• Allergic reactions to vaccine components or any previous vaccination;
• History of allergic reaction to chicken protein;
• History of Guillain-Barré syndrome (acute polyneuropathy);
• 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;
• Use of any vaccines within 1 month before the vaccination, excluding vaccines according to the National Calendar of Preventive Vaccination, including for epidemic reasons;
• History of leukemia, tuberculosis, cancer, autoimmune diseases;
• Positive blood test results for HIV, syphilis, hepatitis B/C.
• Volunteers who received immunoglobulin or blood products or had a blood transfusion during the last three months before the trial;
• History of long-term use (more than 14 days) of immunosuppressants or other immunomodulatory drugs for six months before the trial;
• History of any confirmed or suspected immunosuppressive or immunodeficiency condition;
• 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);
• History of progressive neurological pathology, convulsive syndrome; Diabetes mellitus, thyrotoxicosis or other diseases of the endocrine system;
• History of eczema;
• 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 during the last three months);
• According to the medical history, the volunteer was/is a patient of a tuberculosis dispensary and/or narcological dispensary and/or neuropsychiatric dispensary and/or other;
• History of acute infectious diseases (recovery less than 4 weeks before vaccination);
• Consumption of more than 10 units of alcoholic drinks per week or history of alcohol addiction, drug addiction or abuse of pharmaceutical products;
• Smoking of more than 10 cigarettes per day;
• Participation in another clinical trial during the last 3 months;
• Pregnancy or lactation;
• Serious concurrent illnesses or pathological conditions not listed above which, in the opinion of the investigator, could complicate the assessment of the results of the trial including pathological deviations from age norms and laboratory norms of blood and urine parameters, which are clinically significant in the opinion of the investigator