Trial of Tolerability, Safety and Immunogenicity of the Flu-M Vaccine in Children Between 6 Months and 9 Years Old

Inclusion Criteria: * For volunteers aged 3 to 9 years: * Healthy children of both sexes aged 3 to 9 years (3 years 0 months 0 days - 8 years 11 months 30 days); * The written and dated informed consent of one of the parents for participation in the trial; * For volunteers aged 6 to 35 months: * Healthy children of both genders aged 6 to 35 months, inclusive (6 months 0 days - 35 months 30 days); * The written and dated informed consent of one of the parents for participation in the trial; * The trial subject of the was born full-term, with the Apgar score of 7-10 points. * For all volunteers: Ability of a volunteer's parents to fulfill the requirements of the Protocol (i.e. to fill out the Patient Diary, come to visit with the volunteer). Exclusion Criteria: 1. History of influenza (including in mothers for children aged 6 to 35 months) or previous influenza vaccination during 6 months before the trial; 2. Positive result of the SARS-CoV-2 test; 3. Vaccination of the pregnant woman in the 2nd-3rd trimester (for the age group of 6 - 35 months) with an influenza vaccine; 4. Vaccination with any vaccine less than 30 days before participating in the trial or scheduled vaccination with any vaccine within 30 days after vaccination with the trial vaccines; 5. A serious post-vaccination reaction (temperature above 40 °C, hyperemia or edema more than 8 cm in diameter at the injection site) 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), encephalopathy; 6. Allergic reactions to vaccine components or any previous vaccination; 7. History of allergic reaction to chicken protein; 8. History of cancer, leukemia, tuberculosis, autoimmune diseases; 9. Carriage of HIV, syphilis, hepatitis B and C in the medical history, including by parents; 10. Children who received immunoglobulin products or transfusions of whole blood or its components less than 3 months before the start of the trial; 11. Long-term use (more than 14 days) of any immunomodulating medicines less than 3 months before the start of the trial; 12. Any confirmed or suspected immunosuppressive or immunodeficiency condition; 13. History of chronic diseases of the cardiovascular, bronchopulmonary, endocrine systems, blood in the acute stage (recovery less than 4 weeks before vaccination) or in the decompensation stage; 14. Children with hemophilia who may develop bleeding after intramuscular injection; 15. History of progressive neurological pathology, convulsive syndrome, afebrile convulsions; 16. History of acute infectious diseases (fever ≥ 37.5°С): recovery less than 2 weeks before vaccination; 17. Participation in another clinical trial less than 3 months before the start of the trial; 18. History of mental illness of the child and the volunteer's parents; 19. The history of the volunteer's parent being registered with a tuberculosis dispensary and/or a narcological dispensary; 20. Maternal history of drug use or alcohol abuse during pregnancy and/or breastfeeding; 21. Pronounced congenital malformations in a child; 22. Suspected developmental delay in a child.