Allergic reactions rare during commercial flights
Click Here to Manage Email Alerts
Key takeaways:
- 2.2% of in-flight medical events were due to allergic reactions.
- These events occurred at a rate of 0.66 per million passengers.
- Most passengers with allergies take precautions before flying.
Approximately 2% to 3% of in-flight medical events are due to allergic reactions, with approximately 0.7 reactions per million passengers, according to a review published in The Journal of Allergy and Clinical Immunology: In Practice.
These rates are 10 to 100 times lower than those reported for accidental allergic reactions to food occurring in the community, Paul J. Turner, FRCPCH, PhD, reader in pediatric allergy and clinical immunology, Imperial College London, and colleagues wrote.
The review of MEDLINE, Embase, PsycINFO and TRANSPORT databases yielded 17 studies with low to moderate risk for bias and no evidence of publication bias published between 1, 1980, and 31, 2022.
A meta-analysis of these studies found a pooled estimate of 2.2% (95% CI, 1.6%3.1%) of in-flight medical events (IMEs) that were coded as due to allergic reactions. When the researchers limited the analysis to the studies that included data for children, the rate was 3.1% (95% CI, 1.5%6.6%).
Rates determined by individual studies ranged from 0.71% of IMEs in a 2021 study with unknown locations to 8.9% of IMEs in a 2005 study in the United States.
The researchers cautioned that most of these studies included both children and adults, so the data should be interpreted accordingly.
Further analysis found that the rate of IMEs due to allergic reactions was 0.66 per million passengers. Rates of IMEs per million passengers in individual studies ranged from 0.13 in a 2001 study from France to 3.6 in a 2011 study from Oceania.
Although the researchers noted that prevalence of food allergy and the number of passengers both have increased over the past decades, there was no evidence that the absolute number or the proportion of IMEs due to allergic reactions had increased as well.
Additional estimates included a rate of 2.7 food-induced allergic reactions per 10,000 person-years, which the researchers called equal to one reaction per 3,600 food-allergic passengers travelling in any 1-year period.
When the researchers assessed passengers with food allergy who fly once per week, this rate increased to 34 per 10,000 person-years.
Also, when the researchers compared passengers with food allergies flying at frequencies equivalent to the average population, rates of unintended allergic reactions were approximately 100 times less than rates for self-reported anaphylaxis on the ground and 10 times less frequent than rates for medically coded anaphylaxis.
These low rates may be attributable to the vast majority of passengers with food allergies taking significant precautions in travel such as choosing alternatives to flight, wiping down their seat areas and bringing their own food to consume, the researchers wrote.
Other explanations include the lack of food or snacks on short-haul flights and the lack of peanuts as in-flight snacks on many flights overall, although IME rates due to allergy have not changed despite these recent changes.
Based on these findings, the researchers called the rate of IMEs caused by food-induced allergic reactions low.
Perspective
Back to Top
This is a really interesting study. It brings some much needed data to a domain that is the source of much stress and anxiety among patients
Overall, I think the paper provides information that many readers will find reassuring—namely, first, that the estimated rate of accidental food allergic reactions occurring during air travel appears to be much lower than the rates reported in other contexts of daily life; and, second, that the long-term trends reported here do not suggest that rates of reported reactions on planes have increased over time, despite the skies being busier than ever with passenger air travel.
However, a few points are worth clarifying. First, the top-line reported rate is indeed extremely low at fewer than one allergic reaction per flight per million passengers. Obviously, this includes a lot of people who are not at risk an allergic reaction because they do not have allergies.
In the study, the authors helpfully provide a diagram that compares the risk experiencing a food-allergic reaction during air travel among people with food allergy and then situates that within the context of other risks such as being struck by lightning or dying in a fire.
For frequent flyers, the rate of experiencing an allergic reaction documented as an in-flight medical emergency on a flight approaches the risk ending up in the ED due to a car accident, which I think is an interesting parallel our society has taken a wide variety of efforts to reduce the frequency of such events, including changing the way we build our infrastructure to make roads safer and promoting how individuals can reduce their own risk with seatbelt and helmet laws and PR campaigns to prevent impaired driving.
In contextualizing the long-term trends, it also is important to note that these data only count accidental food-allergic reactions that were documented in the corresponding reporting system. Therefore, their validity assumes that these systems are doing a good job of capturing such events.
The estimates also “bake in” the fact that food allergy patients and their caregivers may be increasingly effective in self-managing and avoiding or promptly treating reactions, owing to greater awareness of food allergy and more frequent passenger carriage of epinephrine autoinjectors (EAIs) on airplanes, irrespective of any actions being taken by the airlines themselves.
Also, if an increasing number of patients with food allergy at particularly elevated risk allergic reactions are deciding not to fly due to concerns (well-founded or not) about the safety of air travel, or a lower proportion of true reactions are making their way into these reporting systems for whatever reason, this also would bring these estimated rates down.
In a collaborative global survey that my colleagues and I presented earlier this year, roughly 40% of accidental food-allergic reactions participants experienced during air travel were not reported to either airline crew or the airline after the fact, meaning they would not be captured by any of these reporting systems.
Relatedly, 95% of survey-reported reactions that were treated with epinephrine either were treated with the patient’s own EAI or an EAI obtained from a fellow passenger. In our survey of 6,000 patients, only 5% of such reactions were treated with epinephrine obtained from airline personnel or the airplane’s emergency medical kit.
In any event, I am thankful that Turner and colleagues have assembled these data and reported them so transparently in this manuscript. It highlights both the weaknesses and strengths of current reporting systems and is a solid foundation for further work in this important area.
Reference:
Warren CM, et al. Understanding experiences, barriers, & facilitators of safe airline travel – A global survey of food allergy patients and caregivers. Presented at: AAAAI Annual Meeting; Feb. 24-27, 2023; San Antonio.
Collapse
Read more about
Click Here to Manage Email Alerts