Due to low enrollment

This pilot study will investigate B-cell responses following vaccination with live, attenuated influenza vaccine (LAIV) in healthy children 2 years of age from blood samples taken at designated time points before and after vaccination.

This is an exploratory study to determine the peripheral antibody secreting cell response during Days 5-13 after immunization with live, attenuated influenza vaccine (LAIV).

Investigators hoped to enroll 27 healthy children, 2 years of age who had not had any prior LAIV or trivalent inactivated vaccine (TIV) within the past 2 years. Due to low enrollment, the study was halted. Due to the limited number of samples, no analysis was performed.

Inclusion Criteria

1. Otherwise healthy children, aged 24-35 months of age, inclusive.
2. Parent(s) or guardian(s) willing to sign informed consent.
3. Availability for follow-up for the planned duration of the study.
4. Acceptable medical history by screening evaluation and brief clinical assessment.
5. Able to understand and comply with planned study procedures

Exclusion Criteria

1. Prior vaccination with LAIV.
2. TIV vaccination during two prior influenza vaccine seasons
3. Known prior MD diagnosis of, or hospitalization for influenza
4. History of asthma, active/recurrent wheezing or reactive airways disease
5. History of immunodeficiency
6. Known or suspected impairment of immunologic function including, but not limited to, clinically significant liver disease; diabetes mellitus; moderate to severe kidney impairment.
7. Known underlying medical conditions (e.g. hemoglobinopathy, congestive heart failure) predisposing to influenza complications.
8. Household contact with immunodeficiency due to disease, medication or radiation
9. Child receiving aspirin therapy or aspirin-containing therapy
10. History of Guillain-Barré syndrome
11. Malignancy, other than squamous cell or basal cell skin cancer
12. Autoimmune disease
13. Use of immunosuppressive medication. Corticosteroid nasal sprays are permissible.
14. Use of antiviral agents against Influenza A and/or B (such as Tamiflu, Relenza, Flumodine, Symmetrel) less than 48 hours before and/or less than two weeks after administration of FluMist.
15. History of blood dyscrasias, renal disease, or hemoglobinopathies requiring regular medical follow-up or hospitalization during the preceding year.
16. Use of investigational agents within 30 days prior to study
17. Receipt of blood products or immunoglobulin in the past 6 months
18. Donation of the equivalent of a unit of blood within 6 weeks prior to enrollment
19. Acute febrile illness on the day of vaccination
20. Known allergies to any component of the vaccine, including eggs or egg products, gentamicin, gelatin,or arginine, or known life-threatening reactions to previous influenza vaccinations.
21. Concurrent participation in other investigational protocols or receipt of an investigational product within the previous 30 days or planned receipt of an investigational product within 28 days following the last immunization dose.
22. Any condition that, in the opinion of the investigator, might interfere with study objectives