To provide Centers for Biologics Evaluation and Research (CBER) with sera collected from healthy children receiving the 2006-2007 formulation of the inactivated, split-virion influenza vaccine Fluzone® for further study by the Food and Drug Administration (FDA), Center for Disease Control and Prevention (CDC) and World Health Organization (WHO).

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 (5.5 lbs).

Exclusion Criteria:

• Reported allergy to egg proteins, chicken proteins, or any other constituent of the vaccine.

• An acute illness with or without fever (For infants/toddlers: temperature

  ≥ 100.4 °F rectal; For children: temperature ≥ 99.5 °F oral/axillary) 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 personal 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 the day of vaccination for 14 days post-vaccination (Influenza vaccine-primed) and for 42 days post-vaccination (Influenza vaccine-naive) participants.