Comparative study of tolerability, reactogenicity, safety and immunogenicity Flu-M [Inactivated Split Influenza Vaccine] vs. the Ultrix® vaccine for the prevention of influenza in pregnant women in the 2nd-3rd trimesters of pregnancy

This is a randomized, double-blind, comparative, controlled trial. A design with a control group treated with Ultrix®, inactivated influenza vaccine, was chosen to obtain objective findings.Trial population: healthy women aged 18 to 35 years during the 2nd and 3rd trimesters of pregnancy. Subjects were randomized into 4 groups in a ratio of 1:1:1:1, 50 subjects per group.

Inclusion Criteria:

1. Presence of signed Informed Consent of the female patient to participate in the trial
2. Healthy women aged 18 to 35 years in their 2nd and 3rd trimesters of pregnancy with gestational age of no more than 32 weeks
3. Singleton pregnancy progressing normally
4. No contraindications for vaccination
5. Pregnant women that are able to fulfill the requirements of the protocol (i.e., fill out the Self-Observation Diary, come to follow-up visits)
6. The investigator is given the opportunity to collect data about somatic, infectious, and allergic diseases within at least 3 months from vaccination (one or more calls from the clinical investigator or visits per month (as needed))

Exclusion Criteria:

1. Body temperature above 37°С
2. History of influenza or previous influenza vaccination during 6 months before the screening
3. History of allergic reactions to chicken protein
4. Allergic reactions to vaccine components or any previous vaccination
5. Gestational toxicosis
6. Any disorders of pregnancy
7. Thyroid disorders
8. Bronchial asthma
9. Clotting disorders
10. 1, 2 type diabetes mellitus
11. High risk of fetal chromosomal abnormalities (individual risk of at least 1/100) in the 1st trimester of pregnancy and/or the detection of fetal congenital anomalies / developmental defects in the 1st, 2nd, and 3rd trimesters of pregnancy
12. Strong 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 from prior vaccination; convulsions accompanied or not accompanied by a fever due to any prior vaccination
13. Acute infectious or non-infectious diseases less than 4 weeks before the screening, exacerbation of chronic diseases (the vaccination can be carried out after recovery or in the period of remission)
14. Immunomodulatory therapy, including immune-enhancing, immunosuppressive therapy (corticosteroids, cytotoxic and radioactive drugs) in the 6 months preceding the trial
15. Any other contraindications against vaccination according to the investigator.
16. Leukemia, cancer or a positive reaction to HIV infection, hepatitis B and C, syphilis in the medical history
17. Volunteers who received immunoglobulin or blood products within the last three months before the trial
18. History of Guillain-Barré syndrome (acute polyneuropathy)
19. Autoimmune diseases
20. Any confirmed or suspected immunosuppressive or immunodeficiency condition
21. Respiratory, cardiovascular failure, impaired liver or kidney function.
22. Severe birth defects or serious chronic diseases, including any clinically significant chronic diseases of lungs, kidneys, cardiovascular, nervous system, psychiatric diseases or metabolic disorders, confirmed by medical history or objective examination
23. Vaccination with any vaccine less than 30 days before the screening or scheduled vaccination with any vaccine within 30 days from vaccination with the trial vaccines
24. The woman is/was a patient of a tuberculosis dispensary and/or narcological dispensary and/or neuropsychiatric dispensary
25. Chronic alcohol abuse and/or use of drugs in the past history
26. Smoking
27. Participation in another clinical trial during the last 3 months

Healthy women aged 18 to 35 years during the 2nd and 3rd trimesters of pregnancy.