- Trial to compare the efficacy of the liquid formulation of CAIV-T with TIV against culture confirmed influenza illness in children.

• The purpose of this study is to compare the efficacy of the liquid formulation of CAIV-T with TIV against culture confirmed influenza illness in children with a history of recurrent RTIs aged at least 6 months and less than 72 months of age.
• The trial also provides the opportunity to compare the efficacy of CAIV-T with TIV on acute otitis media.

Inclusion Criteria:

• who are aged at least 6 months and less than 72 months of age at the time of enrolment;
• who have experienced two or more practitioner attended RTIs* in the past 12 months (since birth if less than 12 months old); * RTIs are defined as upper RTIs including (but not limited to) common cold, acute otitis media and lower RTIs including (but not limited to) bronchiolitis, bronchitis and pneumonia.
• 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 for duration of the trial;
• whose parent(s)/legal guardian(s), can be reached by study staff for the post-vaccination contacts [telephone, clinic or home visit].

Exclusion Criteria:

• whose 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 of a dose equivalent to (i) 2mg/kg/day or greater of Prednisolone or (ii) equivalent to a total of 20 mg/day or greater for children who weigh more than 10kg, for more than 14 days duration until 2 weeks after corticosteroids have been discontinued 27;
• who received any blood products, including immunoglobulin, in the period from six months prior to vaccination through to the conclusion of the study;
• for whom there is intent to administer any other investigational vaccine or agent from one month prior to enrolment through to the conclusion of the study;
• who have an immunosuppressed or an immunocompromised individual living in the same household;
• who, at any time prior to entry into this study, received a dose of any influenza vaccine (commercial or investigational) or is anticipated to receive a non-study influenza vaccine after enrollment;
• with a documented history of hypersensitivity to egg or egg protein or any other component of CAIV-T or TIV;
• who received aspirin (acetylsalicylic acid) or aspirin-containing products in the two weeks prior to enrolment or for which use is anticipated during the study;
• 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 subject is not a contraindication to the enrolment or ongoing participation of the subject in the study.