A Phase II, Trial to Assess the Safety and Tolerability of Influenza Virus Vaccine, CAIV-T in Healthy Children and Adolescents Ages 6 to Less Than 18 Years. (FluMist)

Inclusion Criteria: who are aged 6 to less than 18 years at the time of enrolment who, if female and is of child bearing potential is using reliable method of hormonal and/or non-hormonal contraception (which includes cervical cap, diaphragm, condoms, with spermicide or IUD) during sexual intercourse throughout the entire study period; has provided a negative pregnancy test (with detection limit of less than or equal to 25mL/ml) no more than 24 hours prior to the study vaccine administration and agreed to avoid pregnancy during participation in the study. N.B.lactating females are excluded from the study. who are in good health as determined by medical history, physical examination and clinical judgement whose parent(s)/legal guardian(s) have provided written informed consent after the nature of the study has been explained who, along with their parent(s)/legal guardian(s) will be available until completion of the study whose parent(s)/legal guardian(s), can be reached by study staff for the post vaccination contacts(telephone, clinic or home visit) Exclusion Criteria: who along with their parent(s)/legal guardian(s) 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 who received any blood products, including immunoglobulin, in the period from six months prior to vaccination through to the conclusion of the study 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 components of CAIV-T or placebo who have a history of Guillain-Barre Syndrome (GBS) for whom there is intent to administer any other investigational vaccine or agent from one month prior to enrollment through to the conclusion of the study who, in the two weeks prior to entry into the study, received a dose of influenza treatment (commercial or investigational) who received aspirin (acetylsalicylic acid) or aspirin-containing products in the two weeks prior to enrollment or for which use is anticipated during the study who, at anytime prior to study enrollment, received any influenza vaccine (commercial or investigational) with asthma requiring regular medical follow up or hospitalization during the preceding year with any medical conditions that in the opinion of the investigator might interfere with interpretation of the study results Note: Pregnancy in any person who has regular contact with the subjects is not a contraindication to enrollment or ongoing participation of the subject in the study.