Immunogenicity & Safety of GSK's Avian Flu Vaccine 1557484A Given to Adults Aged ≥18 Years

All subjects will receive 3 doses of study vaccine, including 2 doses of active vaccine and 1
dose of placebo. All subjects will attend formal study center visits for safety and
immunogenicity assessments on Days 0, 10, 42, 182, 192, 224, 549, 559, 591, and 729. A
telephone contact to assess safety will be made at Day 364 and Day 909.

Inclusion Criteria:

- A male or female 18 years of age or older at the time of the first vaccination.

- Written informed consent obtained from the subject.

- Stable health status as defined by absence of a health event satisfying the definition
of a serious adverse event, or a change in an ongoing drug therapy due to therapeutic
failure or symptoms of drug toxicity, within 1 month prior to enrollment.

- Access to a consistent means of telephone contact, which may be either in the home or
at the workplace, land line or mobile, but NOT a pay phone or other multiple-user
device.

- Comprehension of the study requirements, expressed availability for the required study
period, and ability to attend scheduled visits.

- Subjects who the investigator believes can and will comply with the requirements of
the protocol

Exclusion Criteria:

- Presence of evidence of substance abuse or of neurological or psychiatric diagnoses
which, even if clinically stable, are deemed by the investigator to render the
potential subject unable/unlikely to provide accurate safety reports.

- Diagnosed with cancer, or treatment for cancer, within 3 years.

- Persons with a history of cancer who are disease-free without treatment for 3
years or more are eligible.

- Persons with a history of histologically-confirmed basal cell carcinoma of the
skin successfully treated with local excision only are excepted and may enroll
within 3 years of diagnosis, but other histologic types of skin cancer require a
3 year untreated and disease-free window as above.

- Women who are disease-free 3 years or more after treatment for breast cancer and
receiving long-term prophylactic tamoxifen are excepted and may enroll.

- Presence of an oral temperature ≥ 37.8ºC, or acute symptoms greater than "mild"
severity on the scheduled date of first vaccination.

- Any confirmed or suspected immunosuppressive or immunodeficient condition including
history of human immunodeficiency virus (HIV) infection.

- Receipt of systemic glucocorticoids (prednisone >= 10 mg/day for more than 14
consecutive days) within 1 month prior to study enrollment, or any other cytotoxic or
immunosuppressive drug within 6 months of study enrollment.

- Any significant disorder of coagulation or treatment with Coumadin derivatives or
heparin.

- Administration of any vaccines within 30 days before the first study vaccine dose.

- Previous administration of any H5N1 vaccine.

- Use of any investigational or non-registered product (drug or vaccine) or planned
participation in another investigational study within 30 days prior to study
enrollment, or during the 18 months following the first test article dose. Use of any
investigational or non-registered product with immunosuppressive properties is
exclusionary at any time during the trial.

- Receipt of any immunoglobulins and/or any blood products within 6 months of study
enrollment or planned administration of any of these products during the study period.

- Any known or suspected allergy to any constituent of influenza vaccines (including egg
proteins or mercurial preservatives); a history of anaphylactic-type reaction to
consumption of eggs; or a history of severe adverse reaction to a previous influenza
vaccine.

- Known pregnancy or a positive urine beta-human chorionic gonadotropin (β-hCG) test
result prior to vaccination.

- Lactating or nursing.

- Women of child bearing potential who lack a history of reliable contraceptive
practices. The provision of this history does NOT replace the requirement to perform,
and obtain negative results in pregnancy urine tests prior to treatments.

- Known receipt of analgesic or antipyretic medication with the specific intent of
prophylaxis of vaccine reactogenicity on the day of first or any treatment. Subjects
on stable chronic regimens of potentially analgesic or anti-pyretic medications for
pre-existing diagnoses are not required to discontinue them (to do so would represent
evaluation of combined vaccine reactogenicity AND treatment withdrawal - which is not
the intent of the protocol).