Advice for Aircrew
CDC Yellow Book 2024Travel for Work & Other Reasons
As airlines expand their routes to include more destinations, particularly to low- and middle-income countries, aircrew (pilots and flight attendants) need to be prepared for travel-related exposures. Help aircrew protect themselves when traveling for their jobs and when off duty.
Aircrew are distinct from leisure travelers, and the nature of their work requires modifications to travel health recommendations. When consulting with aircrew, consider that they travel frequently; can have short layovers, often 24–48 hours; often travel to new destinations on short notice; might be more adventurous and exposed to more risks than typical tourists, despite short travel times; and that aircrew might perceive themselves to be low-risk since they mostly are healthy, and their in-country exposure time is short.
In general, air carriers that fly to low- and middle-income countries try to inform their crew about the health issues they face. Airlines do not necessarily employ occupational health providers or experts in travel medicine, however, and they can be unaware of special risks at the destinations they serve. Therefore, airlines should avail themselves of travel medicine professionals who can provide well-informed recommendations to their traveling employees.
General Health Measures
When conducting a pretravel consultation for flight crew, ask each crewmember about their airline company’s requirements. If in doubt regarding airline requirements, contact the medical director or occupational health department of the airline for guidance. For example, some airlines might require all aircrew without contraindications to be vaccinated against yellow fever, even those who fly primarily to regions without risk for the disease. Such a policy provides the employer with added flexibility to reassign employees to cover routes that include yellow fever–endemic regions and destinations. In addition, although pilots are required to have periodic medical examinations to ensure they are fit to fly, those visits do not typically address issues related to international travel, particularly to destinations in low-income countries.
Because of their travel frequency, aircrew could be exposed to various diseases that are uncommon in the United States. Measles can be life-threatening in adults and is more common in countries, including some in Europe, that lack mandatory childhood immunization requirements. Measles cases have increased in the United States, with exposures reported to have occurred in airports, and potentially on airplanes. The Centers for Disease Control and Prevention (CDC) has developed recommendations for airlines to help reduce the risk for measles transmission through air travel.
Although US carriers generally do not require pilots and flight attendants to demonstrate adherence to the adult immunization schedule recommended by the Advisory Committee on Immunization Practices, use the pretravel visit as an opportunity to ensure that aircrew are up to date with their vaccines. Check vaccination status for coronavirus disease 2019 (COVID-19), diphtheria-tetanus-pertussis, influenza, measles-mumps-rubella (MMR), polio, as well as age-appropriate vaccines (e.g., pneumococcal vaccine). International aircrew should use the pretravel health visit to ensure as complete protection as possible.
Aircrew also can be at risk for varicella infection. In tropical regions, chickenpox occurs in an older age group than in the United States. Contact with local populations in the tropics can increase the risk for varicella exposure among flight crew who do not have natural or vaccine-induced immunity.
No established guidelines are in effect for recommending travel vaccines to aircrew, but because of their frequent and at times unpredictable assignments to areas of risk, offering Japanese encephalitis, meningococcal, and typhoid vaccines is reasonable (see the relevant disease-specific chapters in Section 5 for details). In addition, consider yellow fever vaccine for aircrew whose unexpected reassignments might include countries that require proof of vaccination against yellow fever under the International Health Regulations (for details, see Sec. 2, Ch. 5, Yellow Fever Vaccine & Malaria Prevention Information, by Country, and Sec. 5, Part 2, Ch. 26, Yellow Fever). Ask about the possibility of itinerary changes so that vaccinations for upcoming trips can be given, or a series started early.
Hepatitis A vaccine is advisable for all travelers and should be stressed for aircrew, since most adults in the United States have not been immunized. Advise aircrew, particularly frequent travelers, to receive hepatitis B vaccine because of the unpredictability of exposure.
Aircrew are generally a group who travel frequently beyond work; during a consultation, always ask whether they are planning other travel, and address those risks at the same time. For example, some aircrew do relief work or fly to areas of natural disasters; consider vaccination against cholera.
Coronavirus Disease 2019
Many international carriers have offered their employees COVID-19 vaccination. The CDC, FAA, and US airlines strongly recommend vaccination against COVID-19 with a product approved or authorized by the US Food and Drug Administration. Pilots are prohibited from flying or serving as a required crewmember within 48 hours after immunization because of possible transient adverse effects (see FAA’s FAQs on Use of COVID-19 Vaccines by Pilots and Air Traffic Controllers).
Advise aircrew not to report to work and to notify their airline’s occupational health program if they are symptomatic or test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Crewmembers should follow current guidance and company policies regarding testing, duration of isolation, mask wearing, and return to work. Aircrew also should contact their airline’s occupational health program after exposure to a person with COVID-19; management guidance (e.g., testing, symptom monitoring, mask wearing, quarantine) should be based on their vaccination status and prior history of SARS-CoV-2 infection.
See FAA’s COVID-19 guidance and resources.
Airlines typically inform crewmembers about which destinations report malaria transmission. Although malaria transmission might occur in some areas of destination countries, sometimes no transmission is reported in the capitals or the larger urban areas (e.g., Manila) where major American carriers fly. In sub-Saharan Africa, however, aircrew can have substantial exposure risk even during a short, 24-hour layover.
Unfortunately, aircrew awareness about malaria and prevention strategies might not be widespread; US and European aircrew traveling to malaria-endemic destinations continue to acquire malaria, including severe and complicated disease. Infections might result from lack of awareness of airline recommendations, failure to take precautions against mosquito bites, or lack of compliance with antimalarial prophylaxis. A small recent survey by Farag and colleagues from the Qatar Ministry of Health revealed that while most aircrew had heard of malaria, many were unaware of the route of transmission, and some were not even sure whether they had traveled to a destination where malaria risk was high.
Help aircrew learn as much as possible about malaria. Provide easy access to educational materials and chemoprophylaxis and, if desired, an individual risk assessment for preventive measures (see Sec. 5, Part 3, Ch. 16, Malaria). Aircrew should understand the importance of personal protective measures and how to use them properly (see Sec. 4, Ch. 6, Mosquitoes, Ticks & Other Arthropods). They should know how take chemoprophylaxis as prescribed; recognize that fever or chills after an exposure is a medical emergency; and know how to get medical assistance at their destinations or at home in the event of symptoms or signs of malaria.
At destinations where the prevalence of malaria is high, prescribe antimalarial medication for aircrew to take even during brief layovers. For some stops (e.g., in West Africa on the way to South Africa), aircrew are at some risk any time aircraft doors are open. Transmission can be focal and intermittent; prescribe chemoprophylaxis for every trip to regions highly endemic for malaria, and stress the importance of taking the full prescription as directed.
Several options are available for malaria prophylaxis depending on the destination, although duration of prophylaxis and adverse effect profiles of drugs make some options less optimal or prohibited for aircrew. Mefloquine, for example, is contraindicated for pilots due to its effects on the central nervous system. International airlines generally recommend that aircrew take the combination drug atovaquone-proguanil because of its minimal adverse effects and its dosing schedule. Country-specific recommendations for malaria chemoprophylaxis can be found in Sec. 2, Ch. 5, Yellow Fever Vaccine & Malaria Prevention Information, by Country, or on the CDC Travelers’ Health website.
For destinations where crew are thought to be at low risk based on local intensity of transmission, accommodations, and personal behaviors, advise taking precautions to prevent mosquito bites without chemoprophylaxis. Few published data are available on the risk for malaria among aircrew with brief layovers, but some suggest that because of the typically shorter duration, risk for aircrew could be less than for tourists. Although risk for malaria transmission in hotels at a destination could be low, it might be greater at international airports due to layovers and unpredictable transit delays.
Other Vectorborne Diseases
During the past decade, several mosquito-borne viruses have emerged or reemerged, including chikungunya, dengue, and Zika (see the individual disease chapters in Section 5). Strict adherence to mosquito bite prevention in tropical and subtropical destinations is critical to preventing disease. Because Zika virus infection during pregnancy can cause severe birth defects, airlines should develop flight destination policies for pregnant aircrew based on CDC recommendations.
Food & Water Precautions: Travelers’ Diarrhea
Aircrew should follow the same safe food and water precautions for prevention and management of travelers’ diarrhea as other travelers (see Sec. 2, Ch. 8, Food & Water Precautions, and Sec. 2, Ch. 6, Travelers’ Diarrhea). Aircrew should also be well versed in the recognition and self-treatment of moderate to severe travelers’ diarrhea to shorten the duration of illness. Gastrointestinal illness can impair job performance and preclude safe operation of an airplane. In addition, pilots should be certain that any antidiarrheal medications they take are approved for use when flying. Loperamide, for example, is not permitted because it can cause drowsiness and dizziness.
Bloodborne & Sexually Transmitted Infections
Although bloodborne pathogen and sexually transmitted infection (STI) risks and preventions are addressed in more detail in other chapters of this book, note that frequent travelers have an increased likelihood of engaging in casual and unprotected sex, and that rates of HIV and other STIs are greater among travelers (see Sec. 9, Ch. 12, Sex & Travel). The risk of acquiring infections might be increased not only for STIs (e.g., chlamydia, gonorrhea), but also for viral illnesses (e.g., hepatitis B, hepatitis C). Because of the risk for bloodborne pathogen infections, discourage aircrew from having dental procedures or participating in activities during travel like acupuncture, piercing, or tattooing.
Screen for tuberculosis (TB) exposure and symptoms and administer a periodic test for TB infection to aircrew who travel frequently to destinations where the prevalence of the disease is greater than in the United States, the incidence of drug resistance to usual TB treatment medication is high, or the crewmember will be in close contact with populations at risk for TB. For more details, see Sec. 5, Part 1, Ch. 23, . . . perspectives: Testing Travelers for Mycobacterium tuberculosis Infection.
Medications for Chronic Conditions
Instruct aircrew to carry extra quantities of all medications for chronic conditions; medications might not be available at some locations, and, even if available and less costly, might be counterfeit or of substandard quality. Counterfeit medications are readily available for purchase in many low- and middle-income countries, and travelers might not be able tell based on the packaging or pills whether drugs are genuine. Some counterfeit drugs contain little or no active ingredient, and others contain toxic contaminants (see Sec. 6, Ch. 3, . . . perspectives: Avoiding Poorly Regulated Medicines & Medical Products During Travel).
Fitness to Fly
Federal Aviation Administration (FAA)–certified aeromedical examiners (AMEs) examine pilots regularly and are responsible for certifying that they are fit to fly. Without prior clearance from the FAA, AMEs might not certify pilots taking prescription or over-the-counter medications known to cause drowsiness (FAA list). Sometimes medication approvals are made on a case-by-case basis. If questions arise, consult an AME (see www.faa.gov/pilots/amelocator to locate an AME).
Do not prescribe medications for pilots that can affect their central nervous system while on duty. Pilots often are aware of some of the medications and classes of medications (e.g., antihistamines) that might interfere with their flight capacity. Pilots who take sedating antihistamines, including chlorpheniramine and diphenhydramine, are not permitted to fly until >5 half-lives have elapsed after the last dose; this equates to a 9-day no-fly rule for chlorpheniramine and a 60-hour no-fly rule for diphenhydramine.
Pilots should not take new medications or drugs before or during travel, whether prescribed or over-the-counter, that have reported side effects known to interfere with judgment or the ability to safely operate a plane. Before providing pilots with nonsedating antihistamines (e.g., desloratadine, fexofenadine, loratadine), ensure the medications can be taken without adverse effect during a trial period.
The FAA prohibits the use of all prescription sleep medication other than zolpidem, which is permitted for use on an infrequent basis (only once or twice per month), and only to reset circadian rhythm. Taking zolpidem results in a 24 hour no-fly period and thus is more appropriate for use at the end of a trip than during a multiday international flight assignment.
Aircrew might have to follow individual airline requirements regarding the allowable time from most recent alcohol consumption to flight duty. The international regulatory expectation is zero alcohol level upon reporting for duty. Warn cabin crew that the alcohol content of beer and other alcohol-containing beverages could be considerably greater at international destinations than what they typically consume at home, which for pilot testing might result in a non–zero alcohol level after a layover overseas. US airline pilots are subject to random alcohol testing, and urine specimens could be collected before or after flights. Although cannabis and cannabinoids are legal in some US states for medical and recreational use, these are prohibited for pilots.
The following authors contributed to the previous version of this chapter: Phyllis E. Kozarsky
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