• Number of subjects with antibody response to the vaccine strain (A/Vietnam/1203/2004) associated with protection 21 days after the second vaccination defined as titer measured by microneutralization (MN) test >= 20. [ Time Frame: 21 days after the second vaccination (= Day 42 in the study) ] [ Designated as safety issue: No ]
  

Inclusion Criteria:

Male and female subjects will be eligible for participation in this study if they:

• Are 18 to 59 years of age on the day of screening (for Stratum A only),
• Are 60 years of age and older on the day of screening (for Stratum B only),
• Have an understanding of the study, agree to its provisions, and give written informed consent prior to study entry,
• Are clinically healthy (in a physical condition such that the physician would have no reservations vaccinating with an influenza vaccine outside the scope of a clinical study),
• Agree to keep a daily record of symptoms,
• If female and capable of bearing children - have a negative urine pregnancy test result at study entry and agree to employ adequate birth control measures for the duration of the study.

Exclusion Criteria:

Subjects will be excluded from participation in this study if they:

• Have a history of exposure to H5N1 virus or a history of vaccination with an H5N1 influenza vaccine,
• Are at high risk of contracting H5N1 influenza infection (e.g. poultry workers),
• Suffer from or have a history of a significant cardiovascular, pulmonary, neurological, hepatic, rheumatic, autoimmune, hematological, metabolic or renal disorder,
• Are unable to lead an independent life as a result of either physical or mental handicap,
• Suffer from any kind of immunodeficiency,
• Suffer from a disease or were undergoing a treatment within 30 days prior to study entry or are currently 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 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 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,
• If female, are pregnant or lactating.