Safety and Immunogenicity Study of GlaxoSmithKline (GSK) Biologicals' Measles, Mumps and Rubella (MMR) Vaccine (209762) Compared to Merck & Co., Inc.'s MMR Vaccine in Healthy Children 12 to 15 Months of Age

This study will evaluate the safety of GSK's trivalent MMR vaccine (referred to as INV_MMR
vaccine) at a potency that will be used to define maximum release limits for the INV_MMR in
comparison to the US standard of care (M-M-R II/ M-M-R VaxPro vaccine referred to as COM_MMR
vaccine). In order to obtain more representative data on the comparator vaccine, the COM_MMR
used in this study will consist of two lots designated COM_MMR_L1 and COM_MMR_L2. Throughout
the study COM_MMR_L1 and COM_MMR_L2 will be analyzed as pooled lots. This study is intended
to support licensure of GSK's MMR vaccine in the US.

All children will receive Varivax and Havrix vaccines, concomitantly with MMR containing
vaccine at 12 to 15 months of age. Prevnar 13 will be administered only to US children. At
the end of the study, GSK will provide a second dose of Havrix and/or varicella vaccine to
participants enrolled in selected non-US countries if local health departments do not
routinely provide hepatitis A and varicella vaccination. The second dose of Havrix and
varicella vaccine is not part of the study procedures.

Inclusion Criteria:

- Male or female child between 12 and 15 months of age (e.g., from the 1 year birthday
until the day before age 16 months) at the time of vaccination.

- Subjects' parent(s)/Legally Acceptable Representative(s) [LAR(s)] who, in the opinion
of the investigator, can and will comply, with the requirements of the protocol.

- Written informed consent obtained from the parent(s)/LAR(s) of the child.

- Child is in stable health as determined by investigator's clinical examination and
assessment of child's medical history.

- For US children only: a child who received all routine vaccinations as per ACIP
recommendations prior to study entry: completion of hepatitis B and rotavirus series
and completion of the primary series of diphtheria, tetanus, pertussis, poliovirus,
Haemophilus influenzae type b (Hib) and pneumococcal vaccines. The 3-dose infant
series of Prevnar 13 should be completed at least 60 days prior to study vaccination.

Exclusion Criteria:

- Child in care.

- Use of any investigational or non-registered product (drug or vaccine) other than the
study vaccine(s) during the period starting 30 days before the day of study
vaccination (i.e., 30 days prior to Day 0) or planned use during the entire study
period.

- Concurrently participating in another clinical study, in which the child has been or
will be exposed to an investigational or a non-investigational product (pharmaceutical
product or device).

- Chronic administration (defined as 14 or more consecutive days) of immunosuppressants,
or other immune-modifying drugs during the period starting 180 days prior to the study
vaccination at Visit 1 or any planned administration of immunosuppressive and
immune-modifying drugs during the entire study.

- For corticosteroids, this will mean prednisone ≥0.5 mg/kg/day or equivalent.

- Inhaled and topical steroids are allowed.

- Planned administration/ administration of a vaccine not foreseen by the study protocol
during the period starting 30 days prior to the day of study vaccination at Visit 1
and ending at Visit 2. Please Note:

- Inactivated influenza (Flu) vaccine and monovalent Haemophilus influenzae type b
conjugate vaccine (Hib) vaccines may be given at any time, including the day of
study vaccination (Flu and Hib vaccines must be administered at a different
location than the study vaccine/s).

- Any other age appropriate vaccine may be given starting at Visit 2 and anytime
thereafter.

- Administration of immunoglobulins and/or any blood products during the period starting
180 days before the study vaccination at Visit 1 or planned administration from the
date of vaccination through the immunogenicity evaluation at Visit 2.

- History of measles, mumps, rubella, varicella/zoster and/or hepatitis A disease.

- Known exposure to measles, mumps, rubella and/or varicella/zoster during the period
starting within 30 days prior to first study vaccination.

- Previous vaccination against measles, mumps, rubella, hepatitis A and/or varicella
virus.

- Any confirmed or suspected immunosuppressive or immunodeficient condition, based on
medical history and physical examination (no laboratory testing required).

- Blood dyscrasias, leukemia, lymphomas of any type, or other malignant neoplasms
affecting the bone marrow or lymphatic systems.

- 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 hypersensitivity to neomycin, latex or gelatin.

- Acute disease at the time of enrollment. (Acute disease is defined as the presence of
a moderate or severe illness with or without fever). Fever is defined as temperature
≥38.0°C/100.4°F by any age appropriate route. All vaccines can be administered to
persons with a minor illness such as diarrhea, mild upper respiratory infection
without fever.

- Active untreated tuberculosis based on medical history.

- Any other condition which, in the opinion of the investigator, prevents the child from
participating in the study.

- For US children only: a child that previously received a fourth dose of PCV-13
vaccine.