Trial purpose is to evaluate the safety, tolerability and reactogenicity of the Vaccine for the prevention of infections caused by Haemophilus Influenzae Type b in volunteers aged 18-50.

The trial includes 2 stages (Stage I and Stage II). The aim of the Stage I is to assess the tolerability, reactogenicity and safety of the Hib vaccine in the first 10 volunteers during the first 7 days after vaccination.

The aim of the Stage I is to assess the tolerability, reactogenicity and safety of the Hib vaccine during 28 days after vaccination and also to conduct a comparative assessment of the safety and reactogenicity of the Hib vaccine and placebo during 28 days after vaccination.

Inclusion Criteria:

• Healthy volunteers (men and women) aged 18-50 years;
• Written informed consent of volunteers to participate in the clinical trial;
• Volunteers not previously vaccinated with any vaccine to prevent infections caused by Haemophilus influenza type b;
• 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 pregnancy test and consent to observe adequate methods of contraception (if hormonal contraceptives are used, they must be canceled at least 2 months before the start of the trial). All women with childbearing potential must have a negative pregnancy test result during the Data Collection Period. In the course of the trial women should use contraception methods with a reliability exceeding 90 %, or be sterile, or be in a postmenopausal state. Contraception methods 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, men and their sexual partners should use contraception methods with a reliability exceeding 90 %, or be sterile. Contraception methods with a reliability exceeding 90 % of common use include cervical caps with spermicide, diaphragms with spermicide, condoms, intra-uterine spirals.

Exclusion Criteria:

• 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, especially to tetanus toxoid, or to any previous vaccination for the prevention of infections caused by Haemophilus influenza type b;
• Guillain-Barré syndrome (acute polyneuropathy) in the medical history;
• 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;
• Vaccination with any vaccine within one month before the vaccination;
• 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 products for six months before the trial;
• History of any confirmed or suspected immunosuppressive or immunodeficiency condition;
• History of chronic diseases of the cardiovascular, bronchopulmonary systems, gastrointestinal tract, liver, kidneys, blood in the acute or decompensation stage;
• History of progressive neurological pathology, convulsive syndrome;
• Diabetes, thyrotoxicosis or other diseases of the endocrine system;
• History of eczema;
• Treatment with glucocorticosteroids, including in small doses, as well as local use of products containing steroids;
• 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;
• Acute infectious diseases less than 4 weeks before the start of the trial according to the anamnesis;
• Consumption of more than 10 units of alcohol per week or history of alcohol addiction, product 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