Safety and Tolerability Study of GlaxoSmithKline (GSK)1557484A Vaccine in Adults at Occupational Risk for Influenza A (H5N1) Exposure

Inclusion Criteria:

- Subjects who, in the opinion of the investigator can and will comply with the
requirements of the protocol.

- Male or female adults ≥18 years of age at time of first study vaccination.

- Written informed consent obtained from the subject.

- Subjects who are at risk of occupational exposure to H5N1 influenza viruses based on
exposure, or potential exposure during either (a) laboratory operations with live
H5N1 virus, (b) production of H5N1 vaccines, or (c) conduct of epidemiological
investigations of H5N1 cases.

- 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 30 days prior to enrollment.

- Female subjects of non-childbearing potential may be enrolled in the study.
Non-childbearing potential is defined as current tubal ligation, hysterectomy,
ovariectomy or post-menopause.

- Female subjects of childbearing potential may be enrolled in the study, if they have
practiced adequate contraception for 30 days prior to vaccination, and have a
negative pregnancy test on the day of vaccination, and agree to practice adequate
contraception for two months following the last dose of vaccine.

Exclusion Criteria:

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

- Presence of a temperature ≥ 38.0ºC (≥100.4ºF) or acute symptoms greater than "mild"
severity on the scheduled date of first vaccination.

NOTE: The subject may be vaccinated at a later date, provided symptoms have resolved,
vaccination occurs within the window specified by the protocol, and all other eligibility
criteria continue to be satisfied.

- Significant risk of complications from intramuscular injections due to disorder of
coagulation. Persons receiving prophylactic antiplatelet medications, e.g., low-dose
aspirin, and without a clinically-apparent bleeding tendency, are eligible.
Assessment of risk of injection complications should be made in the context of
individual subject risk of H5N1 virus infection.

- An acute evolving neurological disorder or Guillain Barré Syndrome within 42 days of
receipt of prior seasonal or pandemic influenza vaccine.

- Administration of an inactive vaccine within 14 days or of a live attenuated vaccine
within 30 days before the first dose of study vaccine.

- Planned administration of any vaccine other than the study vaccine before Day 42.

- Any known or suspected allergy to any constituent of influenza vaccines or component
used in the manufacturing process of the study vaccine including 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 before the first vaccination.

- Lactating or nursing women.

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