How common are allergic reactions during commercial flights? A systematicreview and meta-analysis

Abstract

Global passenger demand for air travel has increased by over 7% annually since 2006, with a strong recovery following the coronavirus disease 2019 (COVID-19) pandemic. Prior to COVID-19, individuals with food allergies reported significant concern and anxiety over the risk of reactions when travelling by air. However, published data of in-flight medical events (IMEs) due to allergic reactions are limited. OBJECTIVE: To undertake a systematic review with meta- analysis to estimate the incidence of IMEs due to allergic re- actions on commercial flights. METHODS: We searched MEDLINE, Embase, PsycINFO, and TRANSPORT databases and the Cochrane Register of Controlled Trials for relevant studies reporting IMEs of allergic etiology, published since 1980. Data were extracted in duplicate for meta-analysis, and risk of bias assessed. Study registration: PROSPERO CRD42022384341. RESULTS: Seventeen studies met the inclusion criteria. At meta- analysis, a pooled estimate of 2.2% (95% confidence interval [95% CI] 1.6%e3.1%) of IMEs are coded as being due to allergic reactions. This may be higher in children (3.1%; 95% CI 1.5%e6.6%). The incidence of allergic IMEs at meta-analysis was 0.7 events per million passengers (95% CI 0.4e1.1). Reas- suringly, the rate of allergic IMEs has been stable over the past 30 years, despite increasing passenger numbers and food allergy prevalence. CONCLUSIONS: Allergic reactions coded as IMEs during commercial air travel are uncommon, occurring at an incidence approximately 10 to 100 times lower than that reported for accidental allergic reactions to food occurring in the com munity. Despite increasing passenger numbers and food al- lergy prevalence, the rate of allergic IMEs has not changed over the past 3 decades.