Safety and Immunogenicity of H5N1 Adjuvanted, Inactivated, Split-Virion Pandemic Influenza Vaccine in Healthy Adults

Inclusion Criteria : * Aged 18 to 40 years on day of inclusion * Informed consent form signed * Able to attend all scheduled visits and to comply with all trial procedures * For a woman, inability to bear a child or negative urine pregnancy test. Exclusion Criteria : * Participation in another clinical trial in the 4 weeks preceding the first trial vaccination. * Planned participation in another clinical trial during the present trial period. * Previous participation in a clinical trial involving an investigational flu pandemic vaccine. * Vaccination with an influenza vaccine during the past 6 months * Any vaccination in the 4 weeks preceding the first trial vaccination * Vaccination planned in the 4 weeks following any trial vaccination * Breast-feeding. * For a woman of child-bearing potential, the absence of an effective method of contraception or abstinence non observed for at least 4 weeks prior to the first vaccination and at least 4 weeks after the last vaccination. * Congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term systemic corticosteroid therapy. * Known human immunodeficiency virus (HIV), hepatitis B (AgHBs) or hepatitis C seropositivity. * Known systemic hypersensitivity to egg proteins, chick proteins, or to any of the vaccine components, or history of a life-threatening reaction to the trial vaccine or a vaccine containing the same substances. * Thrombocytopenia or bleeding disorder contraindicating intramuscular vaccination. * Chronic illness at a stage that could interfere with trial conduct or completion. * Current abuse of alcohol or drug addiction that may interfere with the subject's ability to comply with trial procedures. * Subject deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized without his/her consent. * Blood or blood-derived products received in the past 3 months. * Febrile illness (temperature ≥ 37.5°C) on the day of inclusion. * Laboratory abnormalities considered clinically significant upon the Investigator's judgment in blood sample taken at screening (for Step 1 only)