Study to Evaluate the Efficacy, Safety and Immunogenicity of Influenza Vaccine in Healthy Subjects (Aged 6 to <72 Months) Versus Control Vaccines

Inclusion Criteria

• Children whose parents/legal guardians have given written informed consent prior to study entry: a) aged 6 to <72 months (Part I and II of the study; influenza seasons 2007/2008 and 2008/2009) b) aged 6 to <36 months (Part III of the study; influenza season 2009/2010)
• In good health as determined by: a) medical history, b) physical examination, c) clinical judgment of the investigator

Exclusion criteria

• Administration of licensed vaccines (including H1N1sw vaccines) within 14 days (for inactivated vaccines) or 28 days (for live vaccines) prior to enrollment in this study. Routine vaccines, according to local recommendations, or any other vaccines not foreseen in the protocol could be given after the active trial phase (i.e., 21 days after last vaccination) has been concluded.
• Receipt of another investigational vaccine or any investigational agent within 30 days prior to enrollment in the study or before completion of the safety follow-up period in another study, whichever is longer, and participation in another clinical trial during the present study.
• Experience of a severe acute infectious disease in the month prior to study start or experience of a mild acute infection disease in the week prior the study start (untreated common cold is acceptable). The severity of the infectious disease occurred will be based on the investigator's judgment.
• Any severe acute respiratory disease and infection requiring systemic antibiotic or antiviral therapy ongoing or resolved within 2 days prior to study start.
• Experience an axillary temperature equal to or greater than 37.8°C (rectal temperature equal to or greater than 38.3°C) within the 2 days before enrollment.
• Any serious disease in the opinion of the investigator including, for example: a) cancer, b) autoimmune disease (including rheumatoid arthritis under immunosuppressive therapy), c) insulin dependent diabetes mellitus, d) chronic pulmonary disease, asthma under inhalative therapy only is acceptable, e) acute or progressive hepatic disease, f) acute or progressive renal disease.
• Known or suspected impairment/alteration of immune function, for example, resulting from: a) receipt of immunosuppressive therapy (corticosteroid -except topical or inhaled steroids- or cancer chemotherapy), b) receipt of immunostimulants, c) receipt of parenteral immunoglobulin preparation, blood products, and/or plasma derivatives within the past 90 days and for the full length of the study, d) high risk for developing an immunocompromising disease (suspected or known HIV infection or HIV-related disease).
• Bleeding diathesis.
• History of hypersensitivity to any component of the study medication or chemically related substances.
• History of any anaphylaxis, serious vaccine reactions, or allergy to eggs, egg products or any other vaccine component.
• Laboratory confirmed influenza disease.
• History of neurological disorder or seizures (febrile seizures allowed).
• Received any influenza vaccine.
• Major surgery planned during the study period.
• Any condition which, in the opinion of the investigator, might interfere with the evaluation of the study objectives, e.g., planned travel or relocation of residence that would interfere with completion of study.