Study of the Booster Effect of DTaP-IPV-Hep B-PRP~T Combined Vaccine or Infanrix Hexa™ and Prevenar™ in Healthy Infants

* Aged 12 to 24 months on the day of inclusion.

* Informed consent form has been signed and dated by the parent(s) or other legally acceptable representative (and by an independent witness(es) if required by local regulations).

* Subject and parent/guardian are able to attend all scheduled visits and to comply with all trial procedures.

* Toddlers previously included in Study A3L24 who completed the three-dose primary series vaccination of either DTaP-IPV-Hep B-PRP~T or Infanrix hexa™ at 2,4 and 6 months of age according to protocol (both concomitantly administered with Prevenar™ and Rotarix™).

* Participation in another clinical trial investigating a vaccine, drug, medical device, or medical procedure in the 4 weeks preceding the booster vaccinations.

* Planned participation in another clinical trial during the present trial period.

* Receipt of any vaccine in the 4 weeks preceding the booster vaccinations, except in case of pandemic influenza vaccination, which may be received at least two weeks before the study vaccines.

* Planned receipt of any vaccine in the 4 weeks following the trial vaccinations.

* Previous booster vaccination against pertussis, tetanus, diphtheria, poliomyelitis, Haemophilus influenzae type b, hepatitis B and pneumococcal infection(s) with either the trial vaccine or another vaccine.

* Receipt of blood or blood-derived products in the past 3 months, which might interfere with assessment of the immune response.

* Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 3 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).

* Laboratory-confirmed or clinical suspicion of personal or maternal seropositivity for Human Immunodeficiency Virus (HIV), hepatitis B, or hepatitis C, as reported by the parent/guardian.

* History of pertussis, tetanus, diphtheria, poliomyelitis, Haemophilus influenzae type b, hepatitis B and pneumococcal infection(s), confirmed either clinically, serologically, or microbiologically.

* At high risk for opportunistic infection during the trial.

* Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccine(s) used in the trial or to a vaccine containing any of the same substances.

* History of contraindication to receipt of pertussis-containing vaccine.

* Laboratory-confirmed or clinical suspicion of thrombocytopenia contraindicating Intramuscular vaccination.

* Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination.

* History of seizures .

* Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with trial conduct or completion.

* Receipt of oral or injected antibiotic therapy within 72 hours prior to the first blood draw

* Febrile illness (temperature ≥ 38.0°C) or moderate or severe acute illness/infection (according to investigator judgment) on the day of vaccination.