Frequency of In-Flight Allergic Events Requiring Epinephrine Administration

Two unused anaphylaxis Auto injectors on brightly coloured background. Still has safety cap in place. Clear window contains epinephrine.
How often do in-flight allergic medical events occur that require epinephrine administration, and what is known about these incidents and their outcomes?

Occurrence of an in-flight medical event (IFME) requiring epinephrine administration is rare, with an incidence rate of approximately 1 event per 12.5 million passengers, according to study results published in the Annals of Allergy, Asthma & Immunology.

In December 2020, the American College of Allergy, Asthma, and Immunology and MedAire, a Ground-Based Medical Services (GBMS) provider, signed a memorandum of understanding indicating that MedAir’s confidential database of all reported IFMEs would be analyzed to determine the incidence of in-flight utilization of epinephrine.

Researchers conducted a retrospective study of all allergic events and epinephrine utilization in the database between January 2017 and December 2019.

The researchers specifically sought to evaluate the incidence of in-flight allergic events, including the availability of epinephrine, the use of epinephrine, and the final patient outcome.

The researchers initially retrieved a total of 140,579 IFMEs occurring during the study period, with 3.0% (4230 of 140,579) of these IFMEs identified as allergic events. Of these allergic events, GBMS recommended the administration of epinephrine in 398 passengers, with 82.4% (328 of 398) of them ultimately receiving at least 1 dose of epinephrine.

Per multivariate analysis, a statistically significant difference was observed between the group in whom epinephrine was recommended and was administered (n=328) and the group in whom epinephrine was not administered (n=70) regarding the following:
(1) the involvement of volunteers (odds ratio [OR], 3.19; 95% CI, 2.43-4.16; P <.001); (2) the availability of autoinjectors (OR, 2.00; 95% CI, 1.55-2.58; P <.001); (3) and hospital transport (OR, 6.58; 95% CI, 4.62-9.38; P <.001).

Further, the OR for epinephrine administration is less than 1.00 for passengers aged 12 years and under (OR, 0.36; 95% CI, 0.23 to 0.57; P <.001), which is indicative of this age-group having a lower risk. Those passengers older than 12 years of age were at a statistically significantly higher risk for having epinephrine administered.

Among the 328 passengers who received epinephrine, 22% were transported to the hospital, with 5.2% requiring flight diversion. Overall, 23% of passengers who received epinephrine carried their epinephrine device on board. In the 17 flight diversions among passengers who received epinephrine, 15 occurred in passengers older than 12 years of age and 1 was reported in a passenger less than 6 years of age.

Limitations of the current study are its retrospective design; the inherent challenges in communication between the flight crew, passengers, and GBMS, which could affect data accuracy; and limited data on outcomes beyond hospitalization due to lack of follow-up.

The researchers concluded that “The risk for epinephrine administration is higher in passengers [older than] 12 years of age and is associated with significantly higher flight diversion, hospital transport, and involvement of medical volunteers.” The researchers further noted that “Peanuts and tree nuts are the most frequently implicated triggers,” and that “Passengers and caregivers traveling with a history of allergic reactions should carry medications in person and be prepared to administer autoinjectors early in an emergency.”

Disclosure: One of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.


Kodoth SM, Alves P, Convers K, Davis K, Chang C; Infectious Diseases and International Travel Committee of the ACAAI. The frequency and characteristics of epinephrine use during in-flight allergic events. Ann Allergy Asthma Immunol. Published online August 14, 2022. doi:10.1016/j.anai.2022.08.004