Immunogenicity, Safety and Reactogenicity Study of GlaxoSmithKline (GSK) Biologicals' Hib-MenCY-TT (MenHibrix®) Vaccine Compared to Merck & Co, Inc. PedvaxHIB Vaccine in Healthy Infants and Toddlers 12 to 15 Months of Age

Inclusion Criteria:

- 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.

- A male or female between, and including, 6 and 12 weeks of age at the time of the
first vaccination.

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

- Healthy subjects as established by medical history and clinical examination before
entering into the study.

- Born full-term (i.e. born after a gestation period of at least 37 weeks inclusive).

- Infants who have not received a previous dose of hepatitis B vaccine or those who have
received only 1 dose of hepatitis B vaccine administered at least 30 days prior to
enrollment.

Exclusion Criteria:

- Child in care.

- Use of any investigational or non-registered product (drug or vaccine) other than the
study vaccine(s) within 30 days preceding the dose of study vaccine or planned use
during the study period.

- Chronic administration of immunosuppressants or other immune-modifying drugs since
birth prior to the first vaccine dose. Inhaled and topical steroids are allowed.

- Previous vaccination against Neisseria meningitidis, Haemophilus influenzae type b,
diphtheria, tetanus, pertussis, rotavirus, pneumococcus, hepatitis A and/or
poliovirus; more than one previous dose of hepatitis B vaccine.

- Planned administration/administration of a vaccine not foreseen by the study protocol
in the period starting 30 days before and ending 30 days after the dose of vaccines.
Subjects may receive inactivated influenza vaccine or pandemic influenza vaccines any
time during the study according to the national recommendation. Measles, mumps,
rubella and varicella vaccination are allowed 30 days before or 30 days after the
final vaccination of Hib-MenCY-TT or PedvaxHIB.

- History of Neisseria meningitidis, Haemophilus influenzae type b, diphtheria, tetanus,
pertussis, pneumococcus, hepatitis B, hepatitis A, rotavirus, and/or poliovirus
disease.

- Any confirmed or suspected immunosuppressive or immunodeficient condition based on
medical history and physical examination.

- History of allergic disease or reactions likely to be exacerbated by any component of
the vaccines, including dry natural latex rubber. Hypersensitivity to any component of
the vaccines, including gelatin or neomycin.

- Major congenital defects or serious chronic illnesses.

- History of any neurologic disorders or seizures. A single, simple febrile seizure is
allowed.

- Subjects with history of intussusceptions or uncorrected congenital malformation of
the gastrointestinal tract that would predispose for intussusceptions.

- Acute disease and/or fever at the time of enrollment.

- Administration of immunoglobulins and/or blood products since birth or planned
administration during the study period.