Trial to Investigate Immune Responses Elicited by a Liquid Formulation of Influenza Virus Vaccine (CAIV-T) in Healthy Children (CAIVT)

Inclusion Criteria: children at least 6 months of age and less than 36 months of age at the time of enrollment, and in good health as determined by medical history, physical examination and clinical judgement; whose parent/legal guardian has provided written informed consent after the nature of the study has been explained; who, along with their parent or guardian, will be available for the one month duration of the trial (from enrollment to study completion); Exclusion Criteria: whose parents or guardians are perceived to be unavailable or difficult to contact for evaluation or study visits during the study period; with any serious chronic disease (e.g., with signs of cardiac or renal failure or severe malnutrition), including progressive neurological disease; with Down's syndrome or other known cytogenetic disorders; with a known or suspected disease of the immune system or those receiving immunosuppressive therapy, including systemic corticosteroids, or cytotoxic agents (see Section 4.2.2); have an immunosuppressed or an immunocompromised individual living in the same household; with a documented history of hypersensitivity to egg or egg protein or any other component of the study vaccine, placebo or TIV; who, at anytime prior to study enrollment, receives any influenza vaccine (commercial or investigational); with any medical conditions that in the opinion of the investigator might interfere with interpretation of the study results. Note: A pregnant household member is not considered a contraindication to enrollment.