Comparison of GSK Measles-mumps-rubella-varicella (MMRV) Vaccine Versus PriorixTM

Inclusion Criteria:

• Subjects who the investigator believes that their parents/guardians can and will comply with the requirements of the protocol should be enrolled in the study.
• Male or female subjects between and including 9 and 10 months of age at the time of the first vaccination.
• Written informed consent obtained from the the parent or guardian of the subject.
• Healthy subjects as established by medical history and clinical examination before entering into the study.

Exclusion Criteria:

• Use of any investigational or non-registered product other than the study vaccines within 30 days preceding the first dose of study vaccine, or planned use during the study period.
• Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose.
• Planned administration/administration of a vaccine not foreseen by the study protocol starting 30 days prior to administration of any dose of the study vaccine, up to 42 days after the vaccine dose with the exception of hepatitis A vaccine and oral poliovirus vaccine .
• Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-registered product.
• Previous vaccination against measles, mumps, rubella and varicella.
• History of measles, mumps, rubella and/or varicella diseases.
• Known exposure to measles, mumps, rubella and/or varicella within 30 days prior to the start of the study.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
• A family history of congenital or hereditary immunodeficiency.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccines including neomycin.
• Major congenital defects or serious chronic illness.
• History of any neurologic disorders or seizures.
• Acute disease at the time of enrolment.
• Axillary temperature > 37.5°C (99.5°F) / Rectal temperature > 38°C (100.4°F).
• Administration of immunoglobulins and/or any blood products during the six months before entering the study or planned administration during the study period.
• Presence of a susceptible high-risk person in the same household during the study period.