A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial to Assess the Safety and Tolerability of Influenza Virus Vaccine,(CAIV-T) in Healthy Infants

Inclusion Criteria: * children at least 6 weeks of age and less than 24 weeks of age at the time of enrollment, of \>37 weeks gestational age and with a birth weight of \>2500 g, and in good health as determined by medical history, physical examination and clinical judgment; * whose parent/legal guardian provided written informed consent after the nature of the study was explained; * who, along with their parent or legal guardian, were available for the three month duration of the trial (from enrollment to study completion); * whose parent(s)/legal guardian(s), could be reached by study staff for the post-vaccination contacts \[telephone, clinic or home visit\]. Exclusion Criteria: * whose parents or legal guardians were 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 birth through to the conclusion of the study; * had 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 vaccines or placebo; * who were administered any live virus vaccine within one month prior to enrollment; or expected to receive another live vaccine within 1 month of vaccination in the study. * for whom there was 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) two weeks prior to enrollment. The prophylactic use of influenza antivirals was not permitted; * who, at anytime prior to study enrollment, received any influenza vaccine (commercial or investigational); * with a respiratory illness with wheezing within two weeks prior to each dose of study vaccine; * who received aspirin (acetylsalicylic acid) or aspirin-containing products in the two weeks prior to enrollment or for which use was anticipated during the study; * with any medical conditions that in the opinion of the investigator might have interfered with interpretation of the study results. Note: Pregnancy in any person who had regular contact with the subjects was not considered a contraindication to enrollment.