Primary Objective:

To describe the safety of the 2004-2005 pediatric formulation of the inactivated, split-virion influenza vaccine Fluzone®, given in the two-dose schedule (described in the package insert for vaccine-naïve young children) to the investigational and control groups.

Observational Objective:

To describe the percentage of protective Hemagglutination Inhibition (HAI) antibody titers (following a 2-dose Fluzone® immunization series) to each of the 3 vaccine antigens among the investigational and control groups.

This is an observational and descriptive study that will provide preliminary comparative information about the safety and immunogenicity of Fluzone® vaccine among children aged 6 to 12 weeks (the investigational group, also referred to as the 2-month-old group) versus children aged 24 to 36 weeks (the control group, also referred to as the 6-month-old group). The study is not designed to achieve any preset statistical power, and no hypotheses will be tested.

Inclusion Criteria :

• Aged 42 to 84 days (6 to 12 weeks) or 24 to 36 weeks on the day of inclusion.
• Born at full term of pregnancy (≥ 36 weeks) with a birth weight ≥ 2.5 kg.
• Considered to be in good health on the basis of reported medical history and history-directed physical examination.
• Available for the duration of the study.
• Parent/guardian willing and able to provide informed consent.
• Parent/guardian able to attend all scheduled visits and comply with all trial procedures.
• Willingness to permit venipuncture or heel stick for purposes of collecting a blood sample.

Exclusion Criteria :

• Reported allergy to egg proteins, chicken proteins or any other constituent of the vaccine.
• Previous history of influenza vaccination or documented history of influenza infection.
• Receipt of any vaccine in the 7 days prior to enrollment.
• An acute illness with fever (rectal temperature ≥ 38.0 °C [or ≥ 100.4 °F]) in the 72 hours preceding enrollment in the trial (defer enrollment).
• Known bleeding disorder.
• Participation in any other clinical trial within 30 days prior to enrollment, or planned participation in another clinical trial prior to termination of the subject's participation in this study.
• Known or suspected impairment of immunologic function or receipt of immunosuppressive therapy or immunoglobulin since birth.
• Personal or immediate family history of congenital immune deficiency.
• Developmental delay, neurologic disorder, or seizure disorder.
• Chronic medical, congenital or developmental disorder that could interfere with trial conduct or completion.
• Known HIV-positive or HBsAg-positive mother.
• Known HIV, hepatitis B (HBsAg), or hepatitis C infection.
• Blood or blood-derived products received in the past 2 months.
• Prior history of Guillain-Barré syndrome.
• Any condition which, in the opinion of the investigator, would pose a health risk to the subject or interfere with the evaluation of the vaccine.