How Common Are Allergic Reactions During Commercial Flights? A Systematic Review and Meta-Analysis

Abstract

Global passenger demand for air travel has increased by over 7% annually since 2006, with a strong recovery following the 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. To undertake a systematic review with meta-analysis to estimate the incidence of in-flight medical emergencies (IMEs) due to allergic reactions on commercial flights. We searched MEDLINE, Embase, PsycINFO, 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. PROSPERO CRD42022384341. 17 studies met the inclusion criteria. At meta-analysis, a pooled estimate of 2.2% (95%CI 1.6%-3.1%) of IMEs are coded as being due to allergic reactions. This may be higher in children (3.1%, 95%CI 1.5%-6.7%). The incidence of allergic IMEs at meta-analysis was 0.7 events per million passengers (95%CI 0.4 to 1.1). Reassuringly, the rate of allergic IMEs has been stable over the past 30 years, despite increasing passenger numbers and food allergy prevalence. Allergic reactions coded as IMEs during commercial air travel are uncommon, occurring at an incidence around 10-100 times lower than that reported for accidental allergic reactions to food occurring in the community. Despite increasing passenger numbers and food allergy prevalence, the rate of allergic IMEs has not changed over the past 3 decades.