Travel Health Evidence

Evidence map

Allergy abroad: what the evidence base looks like

19 publications, 9 of them trials and 5 syntheses. This page describes the shape of that literature rather than summarising its conclusions.

Updated 4 min read 19 citations

Glass vial holding a single dose of oral cholera vaccine beside its packaging
Oral cholera vaccine is one of the few travel vaccines given as a drink rather than an injection. Dvermeirre · CC BY-SA 4.0 · Wikimedia Commons
What the evidence on allergy abroad is made of Of 19 publications on this topic, the breakdown by study type: 5 meta-analysis, 9 randomised trial, 3 review, 2 other. 5932meta-analysis (5)randomised trial (9)review (3)other (2)
19 publications, by study type. Volume is not strength — the same count can be a settled question or a pile of commentary, and which one it is depends almost entirely on this breakdown. Harvested from PubMed and Crossref; publication type as recorded by the source.

What this literature is made of

This is a well-developed evidence base: multiple syntheses sitting on a substantial body of trials. Questions here are usually about applicability rather than about whether an effect exists.

The distinction that matters most is between synthesis and primary research. A meta-analysis pools trials and is the closest thing to a settled answer a field produces. A narrative review is one group's reading of the same material and can be selective without being dishonest. Counting them together, which most citation counts do, obscures exactly the thing you want to know.

When the allergy abroad literature was published Publication years for the 19 papers on this topic, grouped into bands from before 2015 through to 2023 onwards. 2023 onwards13 papersBefore 20153 papers2020-20222 papers2015-20191 papers
Still active. The most recent paper here is from 2026, so this is a field where an answer written today may not hold for long. Publication years as recorded by PubMed and Crossref.

How this page is built

Everything above is computed from the citations this site harvested from PubMed and Crossref, not written by hand. When the weekly harvest finds a new paper on this topic, these counts change and the characterisation changes with them. That is the point: a hand-written claim about how strong an evidence base is starts decaying the day it is written.

Publication type is taken as the source records it. That is imperfect — journals label inconsistently, and a paper indexed as a "review" may be a systematic one — so treat the bands as approximate. They are accurate enough to distinguish a trial literature from a commentary literature, which is the distinction that matters.

Row of jet bridges extending from a terminal pier at Charles de Gaulle Airport
Matti Blume · CC BY-SA 4.0 · Wikimedia Commons

The strongest work on this topic

Ordered by study design first, then recency. The full set is listed in the references below.

  1. Risk of anaphylaxis on commercial flights — Turner PJ, 2025, systematic review
  2. How Common Are Allergic Reactions During Commercial Flights? A Systematic Review and Meta-Analysis — Turner PJ, Mamula J, Laktabi J et al., 2023, meta-analysis
  3. Skin care interventions in infants for preventing eczema and food allergy — Kelleher MM, Cro S, Cornelius V et al., 2021, meta-analysis
  4. Frequency, severity and causes of unexpected allergic reactions to food: a systematic literature review — Versluis A, Knulst AC, Kruizinga AG et al., 2015, systematic review
  5. EAACI food allergy and anaphylaxis guidelines: managing patients with food allergy in the community — Muraro A, Agache I, Clark A et al., 2014, clinical guideline
  6. Early-life peanut oral immunotherapy associated with long-term ingestion and immunologic changes — Dantzer JA, Virkud YV, Cox AL et al., 2026, randomised controlled trial
  7. Exploratory analyses of predictors and correlates of response to omalizumab therapy in patients with multiple food allergies — Chinthrajah RS, Kulis M, Jones SM et al., 2026, randomised controlled trial
  8. PrecISE-a biomarker-stratified adaptive trial of 5 interventions in severe asthma: Final protocol and the baseline cohort — Denlinger LC, Israel E, Moore WC et al., 2026, randomised controlled trial
  9. Effects of pregnancy and lactation prebiotics supplementation on infant allergic disease: A randomized controlled trial — Palmer DJ, Cuthbert AR, Sullivan TR et al., 2025, randomised controlled trial
  10. A pediatric randomized, controlled trial of German cockroach subcutaneous immunotherapy — Zoratti E, Wood R, Pomés A et al., 2024, randomised controlled trial
How much research is there on allergy abroad?
19 publications are indexed here, of which 9 are trials and 5 are syntheses.
Does more research mean a stronger conclusion?
No. Composition matters more than volume — five randomised trials support a claim far better than fifty commentaries, and citation counts do not distinguish between them.
How current is this?
The most recent paper indexed here is from 2026. The set is refreshed weekly from PubMed and Crossref.
Why does this page not tell me the answer?
Because summarising a literature into a conclusion requires reading it, and doing that automatically is how confident nonsense gets published. This page tells you how much weight a conclusion could bear; the articles on this site do the interpreting.

References

Every citation below links to the original peer-reviewed record on PubMed or via DOI. Nothing here is a substitute for medical advice.

  1. Risk of anaphylaxis on commercial flights Turner PJ · Current opinion in allergy and clinical immunology · 2025 · Systematic review DOIPubMed 40643054Full text
  2. How Common Are Allergic Reactions During Commercial Flights? A Systematic Review and Meta-Analysis Turner PJ, Mamula J, Laktabi J, et al. · The journal of allergy and clinical immunology. In practice · 2023 · Meta-analysis DOIPubMed 37507067
  3. Skin care interventions in infants for preventing eczema and food allergy Kelleher MM, Cro S, Cornelius V, et al. · The Cochrane database of systematic reviews · 2021 · Meta-analysis DOIPubMed 33545739Full text
  4. Frequency, severity and causes of unexpected allergic reactions to food: a systematic literature review Versluis A, Knulst AC, Kruizinga AG, et al. · Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology · 2015 · Systematic review DOIPubMed 24766413
  5. EAACI food allergy and anaphylaxis guidelines: managing patients with food allergy in the community Muraro A, Agache I, Clark A, et al. · Allergy · 2014 · Clinical guideline DOIPubMed 24905609
  6. Exploratory analyses of predictors and correlates of response to omalizumab therapy in patients with multiple food allergies Chinthrajah RS, Kulis M, Jones SM, et al. · The Journal of allergy and clinical immunology · 2026 · Randomised controlled trial DOIPubMed 41238005Full text
  7. PrecISE-a biomarker-stratified adaptive trial of 5 interventions in severe asthma: Final protocol and the baseline cohort Denlinger LC, Israel E, Moore WC, et al. · The Journal of allergy and clinical immunology · 2026 · Randomised controlled trial DOIPubMed 41707916Full text
  8. Early-life peanut oral immunotherapy associated with long-term ingestion and immunologic changes Dantzer JA, Virkud YV, Cox AL, et al. · The Journal of allergy and clinical immunology · 2026 · Randomised controlled trial DOIPubMed 42167657Full text
  9. Effects of pregnancy and lactation prebiotics supplementation on infant allergic disease: A randomized controlled trial Palmer DJ, Cuthbert AR, Sullivan TR, et al. · The Journal of allergy and clinical immunology · 2025 · Randomised controlled trial DOIPubMed 39173718
  10. A pediatric randomized, controlled trial of German cockroach subcutaneous immunotherapy Zoratti E, Wood R, Pomés A, et al. · The Journal of allergy and clinical immunology · 2024 · Randomised controlled trial DOIPubMed 38718950Full text
  11. Double-Blind, Placebo-Controlled Study of E-B-FAHF-2 in Combination With Omalizumab-Facilitated Multiallergen Oral Immunotherapy Wang J, Wood RA, Raymond S, et al. · The journal of allergy and clinical immunology. In practice · 2023 · Randomised controlled trial DOIPubMed 37087097Full text
  12. One-food versus six-food elimination diet therapy for the treatment of eosinophilic oesophagitis: a multicentre, randomised, open-label trial Kliewer KL, Gonsalves N, Dellon ES, et al. · The lancet. Gastroenterology & hepatology · 2023 · Randomised controlled trial DOIPubMed 36863390Full text
  13. Mepolizumab for urban children with exacerbation-prone eosinophilic asthma in the USA (MUPPITS-2): a randomised, double-blind, placebo-controlled, parallel-group trial Jackson DJ, Bacharier LB, Gergen PJ, et al. · Lancet (London, England) · 2022 · Randomised controlled trial DOIPubMed 35964610Full text
  14. Randomized, double-blind, placebo-controlled, food allergy challenge to olestra snacks Burks AW, Christie L, Althage KA, et al. · Regulatory toxicology and pharmacology : RTP · 2001 · Randomised controlled trial DOIPubMed 11603960
  15. Basophil Activation Test: Bridging Allergy and Oncology for Diagnostic, Therapeutic and Prognostic Applications in AllergoOncology: An EAACI Position Paper Pascal M, Chauhan J, Knol E, et al. · Allergy · 2025 · Review DOIPubMed 40503572Full text
  16. The epithelial barrier theory and its associated diseases Sun N, Ogulur I, Mitamura Y, et al. · Allergy · 2024 · Review DOIPubMed 39370939Full text
  17. The restaurant syndromes Settipane GA · New England and regional allergy proceedings · 1987 · Review DOIPubMed 3302666
  18. Features of acute COVID-19 associated with post-acute sequelae of SARS-CoV-2 phenotypes: results from the IMPACC study Ozonoff A, Jayavelu ND, Liu S, et al. · Nature communications · 2024 · Journal article DOIPubMed 38172101Full text
  19. Global, regional, and national burden of allergic disorders and their risk factors in 204 countries and territories, from 1990 to 2019: A systematic analysis for the Global Burden of Disease Study 2019 Shin YH, Hwang J, Kwon R, et al. · Allergy · 2023 · Journal article DOIPubMed 37431853Full text