trial to compare the safety,tolerability and efficacy of influenza virus vaccine, (caiv-t) with influenza virus vaccine, trivalent, inactivated (tiv) in children

Conditions: Respiratory Tract Infections

Summary: - 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.

Eligibility criteria:
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.