The primary objective of this study was to perform a variety of assays on blood, serum, nasal wash and cell samples obtained from healthy adult subjects for the purposes of developing assays for application in the further investigation of immune responses generated by influenza virus vaccine, trivalent, types A & B, live, cold-adapted (liquid formulation CAIV-T; Wyeth, Marietta, PA).

This was a randomized, open-label, placebo-controlled, outpatient study carried out in healthy adults 18 to < 65 years of age. The study was designed to evaluate the kinetics of the immune responses generated by each of the study products in order to determine the best sampling time for future studies. Subjects were randomized in a 1:1:1 ratio to receive a single dose of either CAIV-T, inactivated influenza virus vaccine (TIV), or placebo.

Inclusion Criteria:

• Subjects had to have been at least 18 years of age and less than 65 years of age at the time informed consent was obtained;
• Women of child-bearing potential had to use reliable methods of hormonal and/or nonhormonal contraception (which includes cervical cap, diaphragm, condoms with spermicide or IUD) during sexual intercourse throughout the entire study period; a negative urine pregnancy test (with detection limit of less than or equal to 25mIU/mL) no more than 24 hours prior to vaccine administration; and agreed to avoid pregnancy during participation in the study. A urine pregnancy test was also conducted at the completion of study participation. Females who were surgically sterile at time of enrollment were not required to undergo pregnancy testing.
• who were determined by medical history, physical examination and clinical judgement to be eligible for the study.
• who provided written informed consent after the nature of the study has been explained;
• who were available for one month duration of the trial (from enrollment to study completion);
• who could be reached by study staff for the post-vaccination contact [telephone, clinic or home visit].

Exclusion Criteria:

• who were perceived to be unavailable or difficult to contact for evaluation or study visits during the study period;
• with a known or suspected disease of the immune system or those receiving immunosuppressive therapy, including systemic corticosteroids and intranasal steroids; or cytotoxic agents;
• who had an immunosuppressed or an immunocompromised individual living in the same household;
• who had a documented history of hypersensitivity to egg or egg protein or any other component of the study vaccine or placebo;
• who received any commercially-available or investigational injected influenza vaccine in the 6 months prior to enrollment, or a non-study influenza vaccine since enrollment;
• who previously received an intranasally administered influenza vaccine;
• who had any medical conditions that, in the opinion of the investigator, might interfere with interpretation of the study results;