Immunogenicity Study of Antibody Persistence and Booster Effect of PENTAXIM™ at 18 Months in Healthy Argentinean Infants

Inclusion Criteria: * Toddler at 18 months of age (range: 510 days to 578 days of age inclusive) * Participated in study A3L02 (NCT00831311) and has completed the three-dose primary series with either diphtheria, tetanus, pertussis (2-component acellular), recombinant Hepatitis B Hansenula and poliomyelitis vaccine adsorbed, and Haemophilus influenzae type b vaccine, conjugated to tetanus protein (DTaP-IPV-HB-PRP\~T) or PENTAXIM™ and ENGERIX B® PEDIATRICO at 2, 4, and 6 months of age * Written informed consent form signed by at least one parent or by a legal representative and an independent witness * Able to attend all scheduled visits and to comply with all trial procedures. Exclusion Criteria: * Participation in another clinical trial in the four weeks preceding the trial vaccination * Planned participation in another clinical trial during the present trial period * Congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months or long-term systemic corticosteroids therapy * Systemic hypersensitivity to any of the vaccine components or history of a life-threatening reaction to a vaccine containing the same substances * Chronic illness at a stage that could interfere with trial conduct or completion * Blood or blood-derived products received in the last six months * Any vaccination in the four weeks preceding the trial * Vaccination with a vaccine containing diphtheria, tetanus, pertussis, Haemophilus influenzae type b, polio, or hepatitis B antigen, since the end of the primary series * History of documented diphtheria, tetanus, pertussis, Haemophilus influenzae type b, polio, or hepatitis B infection(s) (confirmed either clinically, serologically, or microbiologically) * Thrombocytopenia or bleeding disorder contraindicating intramuscular vaccination * History of seizures * Fever (axillary temperature ≥37.4°C or equivalent rectal temperature ≥38.0°C) or acute illness on the day of inclusion * Known contraindication to further vaccination with a pertussis vaccine such as: * Encephalopathy; Inconsolable crying for \>3 hours within 48 hours following vaccine injection * Hypotonic hyporesponsive episode within 48 hours following vaccine injection * Seizures with or without fever within three days following vaccine injection * Axillary temperature \>39.4°C or equivalent rectal temperature \> 40.0°C within 48 hours following vaccine injection.