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

Inclusion Criteria : All Subjects * Subject and parent(s)/legal representative able to attend all scheduled visits and to comply with all trial procedures. * Completion of vaccination according to the national immunization schedule Subjects Aged ≥ 2 Years to \< 18 Years: * Aged ≥ 2 years to \< 18 years on the day of inclusion. * Provision of Informed Consent Form signed by the subject's the parent(s)/legal representative (and by an independent witness if required by local regulations). In addition, provision of Assent Form signed by subjects aged 8 to 11 years, and of Informed Consent Form signed by subjects ≥ 12 years. * For a female of child-bearing potential, avoid becoming pregnant (use of an effective method of contraception or abstinence) for at least 4 weeks prior to each vaccination, until at least 4 weeks after each vaccination. Subjects Aged ≥ 6 Months to \< 2 Years: * Aged ≥ 6 months to \< 2 years on the day of inclusion. * Born at full term of pregnancy (≥ 37 weeks) with a birth weight ≥ 2.5 kg. * Provision of Informed Consent Form signed by the parent(s) or other legal representative (and by an independent witness if required by local regulations). Exclusion Criteria : All subjects * Participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding trial vaccination * Planned participation in another clinical trial during the present trial period * Known or suspected congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term systemic corticosteroids therapy * Known systemic hypersensitivity to any of the vaccine components or history of a life-threatening reaction to the trial vaccine or to a vaccine containing any of the same substances * Chronic illness, at a stage that could interfere with trial conduct or completion, in the opinion of the investigator * Current alcohol abuse or drug addiction 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 trial vaccination * Planned receipt of any vaccine in the 4 weeks following any trial vaccination * (Known) Human Immunodeficiency Virus (HIV), Hepatitis B surface (HBs) antigen or Hepatitis C seropositivity * Previous vaccination against avian influenza with either the trial vaccine or another vaccine * Thrombocytopenia, bleeding disorder or anticoagulants in the 3 weeks preceding inclusion contraindicating IM vaccination * Subjects deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized without his/her consent * Received oral or injected antibiotic therapy within the 72 hours prior to any blood draw Subjects Aged ≥2 Years to \<18 Years: * For a female of child-bearing potential, known pregnancy or positive urine pregnancy test * Breast-feeding female * Febrile illness (temperature ≥ 37.5 °C) or moderate or severe acute illness/infection on the day of vaccination, according to investigator judgment Subjects Aged ≥ 6 Months to \< 2 Years: * History of seizures * Febrile illness (temperature ≥ 38 °C) or moderate or severe acute illness/infection on the day of vaccination, according to investigator judgment.