Trial To Assess Safety And Efficacy Of Influenza Virus Vaccine, Trivalent, Types A & B, Live Cold-Adapted (CAIV-T) In Adults Aged 60 Years And Older

Inclusion Criteria: * who are and aged at least 60 years or older at the time of enrollment; * who are determined by medical history, physical examination and clinical judgement to be eligible for this study. Subjects with stable pre-existing disease, defined as disease not requiring change in therapy or hospitalization within 12 weeks before receipt of study vaccination will be eligible. * who have provided written informed consent after the nature of the study has been explained; * who, will be available for duration of the trial (from enrollment to approximately November 30, 2001); who can be reached by study staff for the post-vaccination and weekly surveillance contacts \[telephone, clinic or home visit\]. Exclusion Criteria: * who are perceived to be unavailable or difficult to contact for evaluation or study visits during the study period; * who are a resident of a nursing home or long-term care facility or other institution receiving skilled or semi-skilled nursing care (refer to study manual). An ambulatory subject who is a resident of a retirement home or village is eligible for the trial. * With evidence of dementia or other severe cognitive impairment based on Mini Mental State Examination (MMSE) scores (refer to study manual). * 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 component of the study vaccine or placebo; * who were administered any live virus vaccine within one month prior to enrollment or expected to receive another live virus vaccine within one month of vaccination in this study; * 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, received a dose of influenza treatment (commercial or investigational) one month prior to enrollment. The prophylactic use of influenza antivirals is not permitted. * who receive any influenza vaccine in the 6 months to enrollment, or a non-study influenza vaccine since enrollment; * 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