How Common Are Allergic Reactions During Commercial Flights? A Systematic Review and Meta-Analysis
Bibliographic record
Abstract
BackgroundGlobal 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.ObjectiveTo undertake a systematic review with meta-analysis to estimate the incidence of IMEs due to allergic reactions on commercial flights.MethodsWe 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.ResultsSeventeen studies met the inclusion criteria. At meta-analysis, a pooled estimate of 2.2% (95% confidence interval [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%–6.6%). The incidence of allergic IMEs at meta-analysis was 0.7 events per million passengers (95% CI 0.4–1.1). Reassuringly, the rate of allergic IMEs has been stable over the past 30 years, despite increasing passenger numbers and food allergy prevalence.ConclusionsAllergic 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 community. Despite increasing passenger numbers and food allergy prevalence, the rate of allergic IMEs has not changed over the past 3 decades. 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. To undertake a systematic review with meta-analysis to estimate the incidence of IMEs due to allergic reactions on commercial flights. 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. Seventeen studies met the inclusion criteria. At meta-analysis, a pooled estimate of 2.2% (95% confidence interval [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%–6.6%). The incidence of allergic IMEs at meta-analysis was 0.7 events per million passengers (95% CI 0.4–1.1). 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 approximately 10 to 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.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.011 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.005 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".