Trial of Tolerability, Reactogenicity, Safety and Immunogenicity of Flu-M [Inactivated Split Influenza Vaccine] in Pregnant Women

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