529. A Three-Year Postmarketing Evaluation of the Frequency of Use and Safety of Live Attenuated Influenza Vaccine in Non-recommended Children Less Than 60 Months of Age
Session: Poster Abstract Session: Influenza Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
  • 529_GerryJohnson_ChristopherAmbrose.pdf (165.7 kB)
  • Background: The 2007 US approval for live attenuated influenza vaccine (LAIV) in children aged 24–59 months included warnings and precautions against use in children aged <24 months (1), children aged 24–59 months with recurrent wheezing (2), individuals with asthma (3), and altered immunocompetence (4). A 3-year postmarketing commitment was initiated to monitor LAIV use and safety in these pediatric cohorts.

    Methods: Children were identified from a national, anonymized insurance claims database covering 17 million individuals. The 4 pediatric cohorts were defined using diagnosis codes and prescription claims. Based on ACIP recommendations, the criterion for identifying children with “recurrent wheezing” was any wheezing in the last 12 months, as evidenced by albuterol dispensing. Rates of LAIV and trivalent inactivated influenza vaccine (TIV) use were calculated, as were the frequencies of hospitalization and emergency department (ED) visits within 42 days postvaccination: all-cause in all cohorts, lower respiratory illnesses (LRI) in cohorts 1–3 and infections in cohort 4.

    Results: In all 3 seasons, compared to children aged 24–59 months overall, LAIV vaccination rates among children in cohorts 1, 3, and 4 were substantially lower, while LAIV use among children with wheezing (cohort 2) was similar. There was no increased rate of total ED visits or hospitalizations within 42 days of vaccination in children vaccinated with LAIV compared with TIV in each of the 4 cohorts. However, for children aged <24 months in the 2009–2010 season, the frequency of LRI was higher in children vaccinated with LAIV compared with TIV.

    Conclusion: Healthcare providers appear to be following the recommendations for the use of LAIV in children aged <5 years; use apparently is not similarly restricted in children with wheezing in the last 12 months. Increased LAIV use in this cohort may be due to the broad vaccination screening criterion in national guidelines. An increased rate of lower respiratory illness in children aged <24 months was consistent with previous randomized, clinical studies of LAIV. Among the limited number of LAIV-vaccinated children aged 24–59 months with asthma, wheezing, or immunocompromise, no safety signals were identified.

    Sponsored by MedImmune, LLC.

    Subject Category: I. Adult and Pediatric Vaccines

    Seth Toback, MD1, Patricia Tennis, PhD2, Elizabeth Andrews, PhD2 and Christopher Ambrose, MD1, (1)MedImmune, LLC, Gaithersburg, MD, (2)RTI Health Solutions, Research Triangle Park, NC


    S. Toback, MedImmune, LLC: Employee, Salary

    P. Tennis, MedImmune, LLC: Consultant and Research Contractor, Consulting fee and Research grant

    E. Andrews, MedImmune, LLC: Consultant and Research Contractor, Consulting fee and Research grant

    C. Ambrose, MedImmune, LLC: Employee, Salary

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