To provide serum to the Food and Drug Administration (FDA) for use by FDA, the Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) for characterization of circulating influenza strains.

Observational Objectives:

To describe the safety of the 2005-2006 pediatric formulation of Fluzone vaccine, given in the two-dose schedule in accordance with the Package Insert, in children aged ≥ 6 months to < 36 months.

To describe the immunogenicity of the 2005-2006 pediatric formulation of Fluzone vaccine, administered in a two-dose schedule in accordance with the Package Insert, in children aged ≥ 6 months to < 36 months.

Inclusion Criteria:

• Participant is aged ≥ 6 months (24 weeks) to < 36 months (3rd birthday).
• Participant is considered to be in good health on the basis of reported medical history and limited physical examination.
• Participant is available for the duration of the study.
• Parent/legal acceptable representative is willing and able to provide informed consent.
• Parent/legal acceptable representative is willing and able to meet protocol requirements.
• Born at full term of pregnancy (≥ 37 weeks) with a birth weight ≥ 2.5 kg.

Exclusion Criteria:

• Reported allergy to egg proteins, chicken proteins, or any other constituent of the vaccine.
• Documented history of influenza infection.
• An acute illness with or without fever (temperature ≥ 100.4 °F, rectal) in the 72 hours preceding enrollment in the trial (Enrollment may be deferred).
• Clinically significant findings in vital signs or review of systems (investigator judgment; defer or exclude).
• Participation in any other interventional clinical trial within 30 days prior to enrollment up to termination of the subject's participation in the 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.
• Known Human immunodeficiency virus (HIV)-positive mother.
• 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.

Adverse events data were collected from day of vaccination for 2 weeks (Influenza vaccine-Primed) and 6 weeks (Influenza vaccine naive) participants.