This study will assess both the antibody persistence of the investigational vaccine and the immune response and safety of a booster dose of PENTAXIM™ vaccine in 18 months-old toddlers who participated in an earlier study in order to determine if they are still protected before they receive a booster dose of D, T, IPV, pertussis or Hib vaccines and also to assess the quality of the induced immune memory in response to a booster dose of the same vaccine as in the primary series.

Primary Objective:

To describe the antibody persistence at 18 months of age and the booster effect of a dose of PENTAXIM™ on immunogenicity.

Secondary objective:

To describe the safety profile of the booster dose PENTAXIM™ in each vaccine group defined by the vaccines received during the primary series.

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.