The objectives of this Phase I/II study are to assess the safety and immunogenicity of two different dose levels of a non-adjuvanted H5N1 influenza vaccine in a healthy young adult population. Subjects will be randomized 1:1 to receive two intramuscular injections (21 days apart) of the vaccine containing either 3.75 µg or 7.5 µg H5N1 hemagglutinin (HA) antigen in a non-adjuvanted formulation. Subjects will be monitored for safety and for antibody response to the vaccine. A data safety monitoring board will review the safety data after the first and second vaccination.

Inclusion Criteria:

• Are 21 to 45 years of age, inclusive, on the day of screening
• Have an understanding of the study, agree to its provisions, and give written informed consent prior to study entry
• Are clinically healthy, as determined by the Investigator's clinical judgment through collection of medical history and performance of a physical examination
• Are physically and mentally capable of participating in the study
• Agree to keep a daily record of symptoms for the duration of the study
• If female and capable of bearing children, have a negative urine pregnancy test result within 24 hours of the scheduled first vaccination and agree to employ adequate birth control measures for the duration of the study.

Exclusion Criteria:

• Have a history of exposure to H5N1 virus or a history of vaccination with an H5N1 influenza virus
• Are at high risk of contracting H5N1 influenza infection (e.g. poultry workers)
• Suffer from or have a history of a significant neurological, cardiovascular, pulmonary (including asthma), hepatic, metabolic, rheumatic, autoimmune, hematological or renal disorder
• Suffer from any inherited or acquired immunodeficiency
• Test positive for Human Immunodeficiency Virus (HIV), Hepatitis B Surface Antigen (HbsAg) or Hepatitis C Virus (HCV)
• Suffer from a disease or are undergoing a form of treatment that can be expected to influence immune response. Such treatment includes, but is not limited to, systemic or high dose inhaled (>800µg/day of beclomethasone dipropionate or equivalent) corticosteroids, radiation treatment or other immunosuppressive or cytotoxic drugs
• Have a history of inflammatory or degenerative neurological disease (e.g. Guillain Barré syndrome)
• Have a history of severe allergic reactions or anaphylaxis
• Have a rash, dermatologic condition or tattoos which may interfere with injection site reaction rating
• Have received a blood transfusion or immunoglobulins within 90 days of study entry
• Have donated blood or plasma within 30 days of study entry
• Have received any live vaccine within 4 weeks or inactivated vaccine within 2 weeks prior to vaccination in this study
• Have undergone systemic corticoid therapy within 30 days prior to study entry
• Have a functional or surgical asplenia
• Have a known or suspected problem with alcohol or drug abuse
• Were administered an investigational drug within six weeks prior to study entry or are concurrently participating in a clinical study that includes the administration of an investigational product
• Are a member of the team conducting this study or are in a dependent relationship with the study Investigator. Dependent relationships include close relatives (i.e., children, partner/spouse, siblings, parents) as well as employees of the Investigator or site conducting the study
• If female: are pregnant or lactating