Immunogenicity and Safety Study of Proquad® and Infanrix® Hexa When Administered Concomitantly (V221-035)

Primary Objective:

* To demonstrate that ProQuad® can be administered concomitantly with a booster dose of Infanrix® hexa to healthy children 12 to 23 months of age without impairing either the antibody response rates to measles, mumps, rubella, varicella, hepatitis B and Haemophilus influenzae type b; or to the 3 pertussis antibody titres measured at 42 days following vaccination.

Secondary Objectives:

* To describe the antibody titres and the antibody response rates to measles, mumps, rubella, varicella, diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and Haemophilus influenzae type b as measured at 42 days following vaccination by an Infanrix® hexa primary series schedule and all data are pooled.
* To evaluate the safety profile of ProQuad® when administered concomitantly with a booster dose of Infanrix® hexa by an Infanrix® hexa primary series schedule and all data are pooled.


Eligibility Criteria:
Inclusion Criteria:

* Healthy participants of either gender
* Aged 12 to 23 months
* No clinical history of measles, mumps, rubella, varicella and zoster
* For Italy: Primary vaccination with the combined diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and Haemophilus influenzae type b vaccine Infanrix® hexa as a 2-dose schedule, with receipt of the second dose ≥ 6 months prior to inclusion
* For Germany: Primary vaccination with the combined diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and Haemophilus influenzae type b vaccine Infanrix® hexa as a 3-dose schedule, with receipt of the third dose ≥ 6 months prior to inclusion
* Consent form signed by parent(s) according to local regulations or by the legal representative properly informed about the study
* Parent(s)/legal representative able to understand the protocol requirements and to fill in the Diary Card.

Exclusion Criteria:

* Prior receipt of measles, mumps, rubella and/or varicella vaccine either alone or in any combination
* Any recent (\<= 30 days) exposure to measles, mumps, rubella, varicella and/or zoster
* Receipt of any other diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and/or Haemophilus influenzae type b containing vaccine (either alone or in any combination) than Infanrix® hexa
* Any recent (\<= 3 days) history of febrile illness
* Any severe chronic disease
* Active untreated tuberculosis
* Known personal history of encephalopathy, seizure disorder or progressive, evolving or unstable neurological condition
* Any known blood dyscrasia, leukemia, lymphomas of any type, or other malignant neoplasms affecting the haematopoietic or lymphatic systems
* Any severe thrombocytopenia or any other coagulation disorder that would contraindicate intramuscular injection
* Prior known sensitivity/allergy to any component of the vaccines including neomycin, sorbitol or gelatin
* Any immune impairment or humoral/cellular deficiency, neoplastic disease or depressed immunity
* Any recent (\<= 2 days) tuberculin test or scheduled tuberculin test through Visit 2
* Any previous (\<= 150 days) receipt of immune serum globulin or any blood-derived products or scheduled to be administered through Visit 2
* Any recent (\<= 30 days) receipt of an inactivated or a live non-study vaccine or scheduled non-study vaccination through Visit 2
* Any medical condition which, in the opinion of the investigator, might interfere with the evaluation of the study objectives
* Any recent (≤30 days) participation or scheduled participation in any other clinical trial through Visit 2