Review of the Safety Evidence for Wheezing: Advisory Committee on Immunization Practices (ACIP) Live, Attenuated Influenza Vaccine (LAIV) Recommendations for Children Aged 24-59 Months

Learning Objectives for this Presentation:
After this presentation participants will understand the safety evidence for ACIP LAIV recommendations to screen for wheezing in children aged 24-59 months.

Background:
In 9/2007, the Food and Drug Administration revised the LAIV (FluMist®) license to include children aged 24-59 months, without a history of asthma or “recurrent wheezing.”

Objectives:
To describe safety evidence that ACIP considered to develop recommendations to screen for wheezing in young children.

Methods:
We reviewed LAIV safety data and ongoing/planned safety monitoring activities in pediatric populations.

Results:
Studies
Risk for wheeze/asthma within 42 days after LAIV was assessed in four studies (>22,000 LAIV recipients aged 6 months–18 years) (Bergen/2004, Peidra/2005, Ashkenazi/2006, Belshe/2007). Three studies enrolled children with wheezing/asthma histories; Bergen excluded children with asthma. Increased risk for wheeze/asthma after LAIV was observed in children aged 18-35 months (Bergen) and 18 months-4 years (1/4 study years) (Piedra). The trial that supported the license revision compared rates of wheeze after TIV with LAIV; rates were higher after LAIV in children aged 6-23 months but not in children aged 24-59 months (Belshe).
Vaccine Adverse Event Reporting System (VAERS)
During 8/2003-2/2007, VAERS received 744 adverse event reports of all ages; 43 (5.8%) were serious. Asthma/wheezing accounted for 6% (16/266) of the reports in the licensed 5-17 year age group.
Ongoing Monitoring
VAERS is conducting surveillance for wheezing/asthma and CDC's Vaccine Safety Datalink will study risks for wheezing/asthma after LAIV.

Conclusions:
Evidence supports the safety of LAIV use in healthy children aged 24-59 months, without a history of asthma or recurrent wheezing. To screen for recurrent wheezing, providers should ask parents: “in the past 12 months, has a healthcare provider ever told you that your child had wheezing or asthma?” LAIV is not recommended if the parent answers yes to this question. This guidance may be modified as new safety data become available.