Immunogenicity & Safety of GSK's Avian Flu Vaccine 1557484A Given to Adults Aged 18-64 Years

The purpose of this observer-blind study is to determine whether GSK's avian flu vaccine GSK 1557484A is immunogenic when given to adults aged 18-64 years.

All enrolled subjects will receive 1 dose of study vaccine. All subjects will attend formal study center visits for safety and immunogenicity assessments on Days 0, 10, 42, 84, and 182 with a telephone safety contact on Day 364.

This Protocol Posting has been updated according to Protocol amendment, 8 Dec 08

Eligibility Criteria:
Inclusion Criteria:

* Male and female adults 18 to 64 years of age at time of first vaccination, inclusive.
* Written informed consent obtained from the subject.
* Stable health status as defined by absence of a health event satisfying the definition of a SAE, 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.
* Presence of an oral temperature \>= 37.8ºC, or acute symptoms greater than "mild" severity on the scheduled date of vaccination.
* Any confirmed or suspected immunosuppressive or immunodeficiency 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.
* An acute evolving neurological disorder or history of Guillain-Barré syndrome within 6 weeks of receipt of seasonal influenza vaccine.
* 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 12 months following test article administration. 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 3 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; 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 vaccination.
* Known receipt of analgesic or antipyretic medication with the specific intent of prophylaxis of vaccine reactogenicity on the day of vaccination. Subjects on stable chronic regimens of potentially analgesic or anti-pyretic medications for pre-existing diagnoses are not required to discontinue them.