Safety and Immunogenicity of Two Doses of H5N1 Influenza Vaccine in Adults Unprimed and Primed With Adjuvanted or Non-adjuvanted Influenza Vaccines

Inclusion Criteria: 1. Subjects aged 18 to 65 years of age, mentally competent, who have signed an informed consent form after having received a detailed explanation of the study protocol; 2. In good health as determined by: 1. medical history, 2. physical examination, 3. clinical judgment of the Investigator; 3. Subjects in the primed group previously received at least two doses of an H5N3 vaccine; 4. Able to understand and comply with all study procedures and to complete study diaries, can be contacted, and will be available for study visits. Exclusion Criteria: 1. Receipt of another investigational agent within 4 weeks, or before completion of the safety follow-up period in another study, whichever is longer, prior to enrollment and unwilling to refuse participation in another clinical study through the end of the study; 2. Subjects who experienced any acute disease or infection requiring systemic antibiotic or antiviral therapy (chronic antibiotic therapy for urinary tract prophylaxis is acceptable) within the past 7 days; 3. Subjects who experienced fever (defined as axillary temperature ≥38.0°C) within 3 days prior to Visit 1; 4. Subjects who are pregnant or breastfeeding; 5. Females of childbearing potential who refuse to use an acceptable method of birth control for the duration of the study. Adequate contraception is defined as hormonal (e.g., oral, injection, transdermal patch, implant, cervical ring), barrier (e.g., condom with spermicide or diaphragm with spermicide), intrauterine device (e.g., IUD), or monogamous relationship with vasectomized partner who has been vasectomized for 6 months or more prior to the subject's study entry; 6. Subjects with any serious disease, such as: 1. cancer, 2. autoimmune disease (including rheumatoid arthritis), 3. diabetes mellitus, 4. chronic pulmonary disease, 5. acute or progressive hepatic disease, 6. acute or progressive renal disease; 7. Subjects for whom a surgery is planned during the study period; 8. Subjects with bleeding diathesis; 9. Subjects with hypersensitivity to eggs, chicken protein, chicken feathers, influenza viral protein, neomycin or polymyxin or any other component of the study vaccine; 10. Subjects with a history of any neurological symptoms or signs, or anaphylactic shock following administration of any vaccine; 11. Subjects with known or suspected impairment/alteration of immune function, for example, resulting from: 1. receipt of immunosuppressive therapy (any corticosteroid therapy or cancer chemotherapy), 2. receipt of immunostimulants, 3. receipt of parenteral immunoglobulin preparation, blood products, and/or plasma derivatives within 3 months prior to Visit 1 or planned during the full length of the study, 4. high risk for developing an immunocompromising disease; 12. Receipt of another vaccine within 3 weeks prior to Visit 1 or planned vaccination within 3 weeks following the last study vaccination; 13. Subjects with a history of (or current) drug or alcohol abuse that in the investigator's opinion would interfere with safety of the subject or the evaluation of study objectives; 14. Subjects with any condition, which, in the opinion of the Investigator, might interfere with the evaluation of the study objectives.