A Study to Evaluate the Shedding and Safety of Trivalent Influenza Virus Vaccine Live, Intranasal in Infants and Young Children

Open label, single arm, multicenter study of the shedding and safety of a single dose of trivalent, influenza virus vaccine live, intranasal in children 6 to \< 60 months of age, with 28-day shedding follow-up and 180-day safety follow-up.

This was a Phase 2, open-label, single-arm, multicenter study designed to evaluate vaccine virus shedding and safety of trivalent influenza virus vaccine live, intranasal in children 6 to \< 60 months of age. Enrollment of approximately 200 participants was stratified by age, with 100 participants 6 to \< 24 months of age (who reached their sixth month but not their second year birthday) and 100 participants 24 to \< 60 months of age (who reached their second year but not their fifth year birthday). Baseline medical history data collection included the participants prior receipt of influenza vaccine or history of laboratory-confirmed influenza illness in the previous influenza season.

Eligibility Criteria:
Inclusion Criteria:

* Male or female, 6 months to less than 60 months of age (reached their 6th month but not yet reached their 5th year birthday) at the time of study vaccination
* Written informed consent and Health Insurance Portability and Accountability Act (HIPAA) authorization obtained from the participants parent/legal representative
* Ability of the participants parent/legal representative to understand and comply with the requirements of the study
* Participants parent/legal representative available by telephone
* Ability to complete follow-up period of 180 days after study vaccination as required by the protocol

Exclusion Criteria:

* History of hypersensitivity to any component of trivalent influenza virus vaccine live, intranasal, including egg or egg products, monosodium glutamate, or porcine gelatin
* History of hypersensitivity to gentamicin
* History of Guillain-Barré syndrome
* Medically diagnosed wheezing, bronchodilator use, or steroid use (systemic or inhaled), by parent/legal representative report or chart review, within the 42 days prior to study vaccination (i.e., children with recent persistent asthma were excluded); or history of severe persistent asthma according to the criteria described in the National Asthma Education and Prevention Program (NAEPP) Expert Panel Report
* Acute febrile (greater than or equal to \[\>=\] 100.0 degree Fahrenheit \[°F\] oral or equivalent) and/or clinically significant respiratory illness (e.g., cough or sore throat) within 72 hours prior to study vaccination
* Any known immunosuppressive condition or immune deficiency disease (including human immunodeficiency virus \[HIV\] infection), or ongoing receipt of any immunosuppressive therapy
* Household contact who was immunocompromised (participants were also to avoid close contact with immunocompromised individuals for at least 21 days after study vaccination)
* Use of aspirin or aspirin-containing products within the 30 days prior to study vaccination, or expected receipt through 180 days after study vaccination
* Use of anti-influenza medications (including amantadine, rimantadine, oseltamivir, and zanamivir) within the 14 days prior to study vaccination, or expected receipt through 28 days after study vaccination
* Use of any intranasal medication within the 14 days prior to study vaccination, or expected receipt through 28 days after study vaccination
* Administration of any live virus vaccine within the 30 days prior to study vaccination, or expected receipt through 30 days after study vaccination
* Administration of any inactivated (i.e., non-live) vaccine within the 14 days prior to study vaccination, or expected receipt through 14 days after study vaccination
* Receipt of any investigational agent within the 30 days prior to study vaccination, or expected receipt through 180 days after study vaccination (use of licensed agents for indications not listed in the package insert was permitted)
* Receipt of any blood product within the 90 days prior to study vaccination, or expected receipt through 28 days after study vaccination
* Family member or household contact who was an employee of the research center or otherwise involved with the conduct of the study
* Any condition that in the opinion of the investigator would have interfered with evaluation of the vaccine or interpretation of study results