Safety and Reactogenicity of a Monovalent Conjugated Vaccine Against Haemophilus Influenzae Type b

Inclusion Criteria: * Infants of either sex, aged 16 - 20 months / 2 - 4 months * in good health as determined by: medical history physical examination clinical judgment of the investigator; * available for all visits scheduled in the study and able to comply with all study regulations; * written informed consent obtained, from at least one parent or legal guardian Exclusion Criteria: * parent or legal guardian is unwilling or unable to give written informed consent to participate in study; * infants who presented a previous disease potentially related to Haemophilus influenzae type b; * infants who had household contact and/or intimate exposure in the previous 30 days to an individual with ascertained Haemophilus influenzae type b disease; * infants who have received any other Haemophilus influenzae type b immunization dose before (for 16-20 months old children who have received a booster vaccination already); * premature (before 37th week of gestation) or birth weight less than 2500 g; * history of anaphylactic shock, asthma, urticaria or other allergic reaction after previous vaccinations or hypersensitivity to any vaccine component; * fever ≥38.0 °C (axillary body temperature) and/or significant acute or chronic infection requiring systemic antibiotic or antiviral therapy within the past 7 days before enrollment; * subjects with any serious chronic disease such as cardiac, neurological, metabolic, hematologic, or neoplastic disease; * known/suspected immunodeficiency, or autoimmune disease, or any immunologic disorder; * subjects with any neurological disorder, e.g., epilepsy or history of seizure disorder; * subjects with a clinically significant genetic anomaly; * treatment with corticosteroids or other immunosuppressive drugs; * treatment with parenteral immunoglobulin preparation, blood products, and/or plasma derivatives (or: within the past 3 months - applicable for children 16 - 20 months); * any vaccination administered within 2 weeks (14 days) before enrollment; * participation in any other investigational trial simultaneously; * planned surgery during the study period; * any condition, which, in the opinion of the investigator, might interfere with the evaluation of the study objective