CDC Yellow Book 2024Preparing International Travelers
It is never too late for a pretravel consultation. Although travelers are encouraged to access pretravel care ≥1 month before departure, clinicians can provide services within days or even hours of departure. As defined by the World Health Organization, the last-minute traveler (LMT) is anyone departing for an international destination on short notice, typically ≤2 weeks. Some reports suggest LMTs comprise up to 16% of a clinic population and include business travelers, relief workers, students, travelers visiting friends and relatives, travelers who planned a trip for some time but delayed seeking pretravel care, or travelers unsuccessful at obtaining an earlier appointment. Regardless of the reason or time constraints, clinicians should offer all travelers support for their upcoming trips.
Pretravel Visit Priorities
Delivering pretravel services to LMTs can be challenging. Typically, LMTs only have time for a single encounter. During the last-minute pretravel consultation, consider what risk-reduction strategies might be necessary to address the following.
Clinic availability. For last-minute appointments, telemedicine services might be an option (for more details, see Sec. 2, Ch. 16, Telemedicine).
Time until departure. Weeks? Days? Hours?
Itinerary vaccinations. What is current vaccine availability? How long before post-vaccination immunity is achieved (e.g., ≥10 days after receiving yellow fever [YF] vaccine)? What are the destination’s vaccine requirements (e.g., YF or meningococcal)? What is the recommendation for vaccines requiring multiple doses?
Traveler’s health status and immunizations. Does the traveler have any preexisting health problems? Do they need booster vaccinations or to complete an unfinished vaccination series?
Resources at destination. What items does the traveler need to carry with them (e.g., adequate medication supply, travel kit items, illness self-treatment options)?
Coronavirus disease 2019. What are the destination requirements for coronavirus disease 2019 (COVID-19) testing or vaccination documentation?
Consider each traveler’s itinerary, trip activities, risk for infection at the destination, and cumulative risk associated with repeat travel. Educate travelers about the value and safety of vaccinations; emphasize preventive behaviors for travelers who might not be adequately protected if they are vaccinated immediately before travel or who do not have sufficient time to complete a vaccine series.
Most travelers who attended school in the United States received routine vaccinations as children. For travelers who are not up to date on vaccinations, provide first or additional vaccine doses, including influenza vaccine, according to Advisory Committee on Immunization Practices (ACIP) schedules, and arrange for return visits as needed.
Recommended Vaccines: Single-Dose Protection
Even with limited time before departure, research supports the use of certain single-dose vaccines, if indicated, to initiate protection in LMTs. These include cholera for selected travelers, hepatitis A (monovalent), meningococcal (quadrivalent, ACWY), polio booster (inactivated), and typhoid (injectable) vaccines. Chapters on the respective diseases in Section 5 provide indications and dosing.
Recommended Vaccines: Multiple Doses Needed
LMTs often cannot complete the schedule of vaccines requiring multiple doses to induce full protection. Carefully evaluate the need for these vaccines, factoring in destination, incidence, and disease severity. If a traveler needs protection against hepatitis B, Japanese encephalitis (JE), or rabies, consider alternative approaches, including use of an approved, accelerated schedule or, depending on expected duration of stay and level of risk, identifying vaccination resources for the traveler at the destination. Travelers should be aware that vaccines received in some countries might be of substandard quality (see Sec. 6, Ch. 3, . . . perspectives: Avoiding Poorly Regulated Medicines & Medical Products During Travel). Because travelers’ level of protection will be unclear if they do not complete a full series of multidose vaccination, provide preventive behavior counseling.
A shortened schedule of 2 doses (at 0 and 28 days) of Heplisav-B vaccine is approved for adults ≥18 years of age. For LMTs with imminent exposure (e.g., disaster relief workers), clinicians can use an accelerated vaccination schedule with Twinrix, the combination hepatitis A and hepatitis B vaccine at 0, 7, and 21–30 days, plus a 12-month booster. Arrange a follow-up visit(s) for short-term travelers to complete the series, and help extended-stay travelers identify resources at their destination to complete the schedule.
In the United States, the JE vaccine, IXIARO, has been approved for use with an accelerated schedule (0, 7 days). For at-risk LMTs who cannot complete the full primary vaccine series ≥1 week before travel, counsel them to strictly adhere to insect precautions. Alternatively, help travelers identify reliable sources for IXIARO vaccination at their destination, or with internationally (but not domestically) available, single-dose JE vaccines, (e.g., Imojev [Sanofi Pasteur] or live attenuated SA 14-14-2 JE vaccine [Chengdu Institute of Biological Products]).
In the United States, rabies preexposure vaccination previously consisted of a series of 3 intramuscular injections of a rabies vaccine given on days 0, 7, and 21 or 28. The ACIP recently revised its recommendations for rabies preexposure vaccination and approved a 2-dose preexposure regimen given on days 0 and 7. This revised schedule has the advantage of being both less expensive and easier to complete prior to travel. There is, however, an absence of data on how long this 2-dose series provides protection against rabies virus exposure. As a result, travelers with a sustained risk for rabies exposure should either have a titer drawn or receive a third dose of vaccine within 3 years of the initial series.
For travelers who started, but did not complete, a rabies preexposure vaccination series and had a potential rabies exposure, provide the same postexposure prophylaxis as for a completely unimmunized person. Regardless of whether travelers are vaccinated or not, emphasize animal avoidance (see Sec. 4, Ch. 7, Zoonotic Exposures: Bites, Stings, Scratches & Other Hazards, Sec 5, Part 2, Ch. 18, Rabies, and Sec 5, Part 2, Ch. 19, . . . perspectives: Rabies Immunization). Encourage travelers to purchase insurance for evacuation or urgent postexposure treatment (see Sec. 6, Ch. 1, Travel Insurance, Travel Health Insurance & Medical Evacuation Insurance). As warranted, offer longer-stay travelers the option to receive the rabies vaccine series at their destination.
Coronavirus Disease 2019
The Centers for Disease Control and Prevention (CDC) advises all eligible international travelers to be up to date with their COVID-19 vaccinations (primary series and booster[s]) before travel.. Travelers should also check to confirm the latest COVID-19 entry requirements at their destination.
Quadrivalent (ACWY) meningococcal vaccine is required for adults and children >2 years of age traveling to Saudi Arabia for religious pilgrimage. Hajj visas cannot be issued without proof that applicants received meningococcal conjugate vaccine ≥10 days and ≤5 years before arriving in Saudi Arabia.
Travelers who receive YF vaccine <10 days before entering a risk area are at risk of infection with YF virus. Documentation of vaccination against YF becomes valid 10 days after administration. When proof of vaccination against YF is required by a country on the traveler’s itinerary, and the LMT is planning to arrive before 10 days have elapsed, clinicians can suggest the traveler rearrange the order of travel or reschedule the trip. Otherwise, the traveler risks being denied entry, quarantined, or revaccinated at the border. In travelers for whom YF vaccine is contraindicated, YF vaccine Uniform Stamp Owners (clinicians designated by their state or territorial health department to administer YF vaccine) can issue a medical waiver letter in lieu of vaccination. See Sec. 5, Part 2, Ch. 26, Yellow Fever, for more details.
Malaria & Other Mosquito-Borne Illnesses
Clinicians must factor in time until departure and local pharmacy supply when considering malaria chemoprophylaxis choices for LMTs, in addition to the usual considerations of cost, drug resistance at destination, itinerary, medical contraindications, and patient preference. For travelers departing in ≤2 weeks, options for malaria chemoprophylaxis include atovaquone-proguanil or doxycycline in addition to education about mosquito avoidance and follow-up for fever. Consider primaquine or tafenoquine only if time allows for glucose-6-phosphate-dehydrogenase (G6PD) screening; do not prescribe either of these drugs without first knowing the traveler’s G6PD status (see Sec. 5, Part 3, Ch. 16, Malaria). Educating travelers about insect avoidance can help them to avoid Zika, dengue, and chikungunya infections at their destination and help to prevent local disease transmission (see Sec. 4, Ch. 6, Mosquitoes, Ticks & Other Arthropods).
Risk-Management Health Counseling
Pretravel counseling is critical for LMTs. Determine travelers’ knowledge and experience in managing travel health risks, and focus on major risks of the trip and special issues for LMTs (see Box 2-12). LMTs benefit most when provided with simple, prioritized messages about prevention and self-care.
Box 2-12 Last-minute travelers (LMTs): supplemental counseling topics
GENERAL PREVENTION MESSAGES
For general prevention messages, see Sec. 2, Ch. 1, The Pretravel Consultation.
Address concerns that “last-minute” consultation visits are “too late.”
Assure travelers that vaccinations, regardless of when they are given, have value, and protective immunity continues to develop.
Although high-risk exposures are possible on arrival to the destination, educate travelers about cumulative risk associated with repeat travel.
Inform travelers where online they can find information on destination medical services:
- US Department of State
- International Society of Travel Medicine clinic directory
Provide resources for health information for international travel:
Encourage LMTs to obtain travel health and medical evacuation insurance.
TRAVEL HEALTH KITS
Educate LMTs that drugs and health kit products purchased abroad might be counterfeit or substandard.
Encourage LMTs to purchase and pack medications for travelers’ diarrhea or altitude illness, over-the-counter drugs, first aid supplies, insect repellent, sunscreen, condoms, and thermometers before leaving the United States (see Sec. 2, Ch. 10, Travel Health Kits).
Inform travelers to check 24-hour pharmacies, airport clinics, and online companies offering overnight or expedited shipping to obtain needed kits or supplies.
Have the LMT return to the clinic after travel to complete any unfinished vaccine series.
Initiate preparation in advance of the next spur-of-the-moment travel.
Travelers Leaving in Less Than 48 Hours
If travel is imminent, clinicians can still provide telehealth or secure digital messaging for prevention counseling and recommendations for services at the destination. During the consultation, emphasize and reassure the LMT that many travel health risks can be prevented by adhering to healthy behaviors.
Travelers with Preexisting Medical Conditions
LMTs with preexisting conditions might be at increased risk for acute episodes of comorbid conditions (see Sec. 3, Ch. 3, Travelers with Chronic Illnesses). These travelers should carry a portable medical record, know reliable sources for medical care at their destination, and purchase travel health insurance, trip insurance, and medical evacuation insurance. In addition, encourage these travelers to schedule a pretravel appointment or conversation with their treating clinician. Some conditions (e.g., immunosuppression, pregnancy), often require additional discussion or advanced planning and could warrant delaying departure (see Sec. 3, Ch. 1, Immunocompromised Travelers, and Sec. 7, Ch. 1, Pregnant Travelers).
A last-minute consultation will not provide adequate time for a full medical and psychological evaluation or additional education for an expatriate. Advise extended-stay travelers to arrange an early consultation with a qualified clinician at their destination.
Traveler Requests: Carrying Vaccines or Off-Label Dosing
Because of time constraints, some LMTs might ask to carry a vaccine abroad or for a vaccine to be administered off-label (e.g., different schedule, double dosing). Due to cold chain concerns, it is rarely advisable to provide travelers with a supplied vaccine. Clinicians who administer a vaccine in a nonstandard manner can face medical-legal issues and induce a false sense of protection in the traveler.
Recurring Last-Minute Travelers
Clinics that frequently see LMTs might want to address this as an administrative issue. The clinical practice could build flexibility into the schedule and proactively identify groups likely to travel last minute (e.g., college students, corporate employees, relief workers). For these travelers, the clinic might consider routine pretravel visits or preemptive vaccinations for certain itineraries.
The following authors contributed to the previous version of this chapter: Gail A. Rosselot
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