Immunogenicity and Safety of an Intramuscular A/H5N1 Inactivated, Split Virion Pandemic Influenza Vaccine in Adults

Inclusion Criteria: * Aged 18 to 60 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. * For a woman of child-bearing potential, use of an effective method of contraception or abstinence for at least 4 weeks prior to and at least 4 weeks after each vaccination. Exclusion Criteria: * Systemic hypersensitivity to any component of the vaccine or a life-threatening reaction after previous administration of a vaccine containing the same substances (egg proteins, chick proteins, thimerosal, aluminum, neomycin, formaldehyde, and octoxinol 9). * Febrile illness (oral temperature \>= 37.5°C) on the day of inclusion. * Breast-feeding. * Previous vaccination with an avian flu vaccine. * Participation in a clinical trial (drug, device, or medical procedure) within 4 weeks prior to the first vaccination. * Planned participation in another clinical trial during the present trial period. * Congenital or acquired immunodeficiency, or receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term systemic corticosteroid therapy. * Chronic illness that could interfere with trial conduct or completion (e.g. cardiac, renal, diabetes, or auto-immune disorders). * Current alcohol or drug abuse that may interfere with the subject's ability to comply with trial procedures. * Receipt of blood or blood-derived products in the past 3 months, that might interfere with the assessment of immune response. * Receipt of any vaccine in the 4 weeks preceding the first trial vaccination. * Planned receipt of any vaccine in the 4 weeks following any trial vaccination. * Thrombocytopenia or bleeding disorder contraindicating intramuscular vaccination. * Subject deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized without his/her consent.