Live Attenuated Influenza Vaccine May Be Safe for Children with Egg Allergies

EBM Focus - Volume 11, Issue 1

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Reference - BMJ 2015 Dec 8;351:h6291 (level 3 [lacking direct] evidence)

  • Current guidelines recommend against using live attenuated influenza vaccine (LAIV) in persons with egg allergy or in children with recent asthma or wheezing episode, but there is limited evidence regarding the vaccine’s safety in these populations.
  • In this study, 779 children with egg allergy were vaccinated with LAIV containing detectable amounts of ovalbumin.
  • No immediate systemic reactions were reported, and rates of delayed adverse events were similar to previously reported rates in non-atopic children and adults.

The Advisory Committee on Immunization Practices recommends against vaccinating persons with egg allergy or young children with asthma or wheezing episode within the previous 12 months with the LAIV (MMWR Morb Mortal Wkly Rep 2015 Aug 7;64(30):818). However, some evidence suggests that influenza vaccination may be safe for adults and children with egg allergies, including those with previous anaphylaxis to eggs (Ann Allergy Asthma Immunol 2012 Dec;109(6):426, J Allergy Clin Immunol 2012 Nov;130(5):1213, J Allergy Clin Immunol 2012 Nov;130(5):1213). To further investigate the safety of LAIV in this population, 779 children aged 2-18 years (median age 5 years, 65% male) with egg allergy were vaccinated with LAIV. LAIV with detectable ovalbumin was specifically used for this study, with 85.6% of children receiving a vaccine with > 0.3 ng/mL ovalbumin and 65.6% receiving between 1-2 ng/mL.

Two hundred seventy children (34.7%) had previous anaphylaxis in response to eggs, with cardiovascular or respiratory symptoms in 157 (20.1%). Most children had also been diagnosed with asthma or recurrent wheeze (57.1%), atopic eczema (59.4%), and/or allergies to ≥ 3 food groups (55.8%). Children were excluded only for previous egg anaphylaxis requiring invasive ventilation, severe asthma, or contraindications for LAIV other than egg allergy. Immediately following immunization, no systemic adverse events were reported. Within 72 hours of vaccination, 28.4% of children had delayed events potentially related to the vaccine including 8.1% of children reporting lower respiratory tract symptoms. The rates of delayed adverse events were similar to those previously reported for non-atopic children and adolescents. No risk factors were identified for predicting the occurrence of immediate or delayed adverse events. At 4 weeks, there was a small but significant improvement in the Asthma Control Test scores for children 2-11 years old with a history of asthma.

While most LAIVs do not contain detectable ovalbumin, this study specifically sourced vaccines with detectable ovalbumin to determine safety. This allowed for the evaluation of the vaccine under a “worst case scenario” when detectable levels of ovalbumin were present. Even under these circumstances, children with egg allergies, including those with previous anaphylactic reactions to eggs, were at low risk for allergic reactions to the seasonal LAIV. Furthermore, young children with a history of asthma or wheezing, another contraindication to vaccination, had slightly lower asthma test scores after vaccination. Together, these results suggest that LAIV may be considered in children with egg allergies or a recent wheezing episode. It would be prudent, however, to administer the vaccine to children and adolescents with a history of egg allergy only at a facility equipped to deal with an acute allergic reaction should one occur.

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