The purpose of this study is to evaluate the safety and immunogenicity of different formulations of GSK Biologicals' H7N9 influenza vaccine in subjects 18 to 64 years of age.

Inclusion Criteria:

• Male or female adults who are 18 to 64 years of age (inclusive) at the time of first study vaccination.

• Written informed consent obtained from subject.

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

• Healthy subjects as established by medical history and physical examination.

• Access to a consistent means of telephone contact.

• For subjects who undergo a screening visit: results of all safety laboratory tests obtained at the screening visit must be within reference ranges. Results of any repeat testing cannot be used to qualify a subject for enrolment.

• 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 continue to practice adequate contraception until 2 months after the last dose administered.

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 or evidence of substance abuse.
• Diagnosed with cancer, or treatment for cancer within three years.
• Diagnosed with excessive daytime sleepiness, or narcolepsy; or history of narcolepsy in a subject's parent, sibling or child.
• Presence of a temperature ≥ 38.0ºC (≥100.4ºF), 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 within 30 days prior to the first dose of study vaccine/placebo, or any other cytotoxic, immunosuppressive or immune-modifying drugs within 6 months of first study vaccine/ placebo dose.
• Any significant disorder of coagulation or treatment with warfarin derivatives or heparin.
• 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/placebo.
• Planned administration of any vaccine other than the study vaccine/placebo before blood sampling at the Day 42 visit.
• Previous administration of any H7 vaccine or physician-confirmed H7 disease.
• Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the first dose of study vaccine/placebo, or planned use during the study period.
• Receipt of any immunoglobulins and/or any blood products within 90 days before the first dose of study vaccine/placebo, or planned administration of any of these products during the study period.
• 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 dose of study vaccine/placebo.
• Lactating or nursing women.
• Any condition which, in the opinion of the investigator, prevents the subject from participating in the study.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.