Approach to the Patient Before and After Travel

Prevention strategies and medical interventions for travelers should be individualized according to a risk assessment that considers both the itinerary and factors that are dependent on the prospective traveler. A structured approach to patient interaction ( Table 265-1 ) is the most efficient way to cover the necessary educational and preventive interventions. Providing clearly printed instructions in lay language is advised. The worldwide epidemiology of travel-related diseases is constantly changing. Special needs travelers, such as individuals who are immunocompromised, pregnant, or have significant underlying disease, should be referred to a specialized travel medicine clinic.

TABLE 265-1

THE PRETRAVEL CONSULTATION WITH A TRAVELER TO THE DEVELOPING WORLD—A STRUCTURED APPROACH

PERFORM RISK ASSESSMENT

The following must always be ascertained initially to determine the appropriate preventive medical recommendations. Preprinted medical record forms may be used to record these .
Exact itinerary, including regions within each country to be visited
Dates of travel to assess risk of seasonal diseases
Age
Past vaccination history
Underlying illnesses
Current medications
Pregnancy status
Allergies
Purpose of trip
Risk exposures—blood, body fluids, adventure, or extensive outdoor exposures
Urban versus rural travel
Type of accommodations
Level of aversion to risk
Review traveler-specific risk with respect to emerging infectious pathogens
Financial limitations that may necessitate prioritization of interventions

ADMINISTER IMMUNIZATIONS

Administer routine vaccinations that are not up to date.
Administer indicated travel vaccines.
Provide to patient legally mandated Vaccine Information Statements from the Centers for Disease Control and Prevention ( http://www.cdc.gov/vaccines/pubs/vis/ ).
Provide printed checklist to patient listing vaccines administered.
Record in the clinic record vaccines administered, lot number, and date.
Document vaccines offered to but declined by patient as well as nonrecommended vaccines administered at the patient’s request.

PROVIDE MALARIA PREVENTION (IF INDICATED)

Determine whether malaria risk exists for the destination country. If yes:
Does the patient’s itinerary within that country put him or her at risk? If yes:
Recommend malaria chemoprophylaxis. Several equally effective drugs of choice may be indicated. Ascertain which is best suited to the individual patient and itinerary.
Educate on personal protection against arthropods.

EDUCATE ON TRAVELER’S DIARRHEA

Recommend food and water precautions.
Educate on use of oral hydration and loperamide and prescribe standby therapy for severe diarrhea with azithromycin or a quinolone.

TEACH ESSENTIAL PREVENTIVE BEHAVIORS

Most travel-related health problems, including vaccine-preventable diseases, can be avoided through simple behaviors initiated by the traveler.
Educate on appropriate strategies in the following categories (some topics are not applicable to all destinations): blood-borne and sexually transmitted diseases, safety and crime avoidance, injury prevention, swimming safety, rabies, skin/wound care, tuberculosis, packing for healthy travel, obtaining health care abroad.

DISCUSS OTHER APPLICABLE HEALTH ISSUES

Advise and prescribe for altitude illness, motion sickness, or jet lag.
Discuss prevention of specific travel-related infections that are of some risk to the traveler and have a possible preventive strategy not included in strategies above.
Discuss any minimal-risk conditions (e.g., hemorrhagic fevers) that are a frequent cause of patient anxiety.
Discuss travel restrictions and advisories; consider additional testing, quarantine, and/or vaccination requirements related to emerging infections.

Globally, approximately 100 million people travel from industrialized to developing countries each year, with risks of travel-related illness determined by the route and destination. Depending on the destination, about 20 to 70% of travelers report some illness, mostly mild, self-limited conditions such as diarrhea, respiratory infections, and skin disorders. Infectious diseases account for up to 10% of the morbidity during travel but only 1% of the deaths, with malaria ( Chapter 316 ) being the most common cause.

Immunization

The choice of vaccines for an individual traveler is based on the risk of exposure to vaccine-preventable diseases on the planned itinerary, the severity of a disease if it is acquired, and any risks presented by the vaccine itself. Travelers differ in their tolerance of risk. For vaccine-preventable diseases, the monthly incidence for nonimmune travelers to developing countries is most significant for influenza (about 1%; Chapter 332 ) and for symptomatic hepatitis A (about 0.03%; Chapter 134 ), but the risk of symptomatic hepatitis B ( Chapter 134 ) is most significant for long-stay travelers (e.g., missionaries) at 0.25% per month. Enteric fever (typhoid and paratyphoid) has a risk of 0.03% per month on the Indian subcontinent and is 10 times lower in Africa and parts of Southeast Asia and Latin America. The risk of contact with animals that could have rabies ( Chapter 383 ) is also substantial, at about 1% per month. The risk of yellow fever ( Chapter 351 ) may be as high as 0.1% per month of travel to an area with current epidemic transmission, but the risk varies greatly among destinations encompassed by the endemic area map. The risk of meningococcal meningitis ( Chapter 274 ), cholera ( Chapter 278 ), polio ( Chapter 349 ), varicella ( Chapter 346 ), and Japanese encephalitis ( Chapter 352 ) in travelers is not known but is thought to be small (<0.0001%). Worldwide measles outbreaks and declining vaccination rates have led to a rise in travel-related measles ( Chapter 338 ). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; Chapter 335, Chapter 336, Chapter 337 ) pandemic created additional risks despite associated travel restrictions.

A number of vaccines ( Table 265-2 ; see also Chapter 15 ) are available for prospective travelers and can be administered in the travel medicine setting when indicated.

TABLE 265-2

TRAVEL-RELATED VACCINES OF ADULTS

DISEASE	VACCINE	PRIMARY COURSE (A: ACCELERATED SCHEDULE)	ROUTE	FURTHER BOOSTERS
VACCINES TO CONSIDER FOR ALL DEVELOPING WORLD TRAVELERS
Hepatitis A	Killed virus	0, 6-18 months	IM	None
Hepatitis B	Recombinant viral antigen	0, 1, 6 months	IM	None
		A: 0, 1, 2 months and 12 months	IM
		A: 0, 1, 3 weeks and 12 months ∗	IM
	Recombinant, adjuvanted	0, 1 month	IM	None
Hepatitis A/B	Combination of monovalent preparations	0, 1, 6 months	IM	None
Hepatitis A/B	Combination of monovalent preparations	A: 0, 1, 3 weeks and 12 months	IM	None
Typhoid	Capsular Vi polysaccharide	Single dose	IM	2 years
Typhoid	Live attenuated Ty21a bacteria	0, 2, 4, 6 days	Oral	5 years
Influenza	Inactivated viral	Single dose	IM	Annual
Influenza	Live attenuated virus	Single dose (<50 years of age only)	Nasal	Annual
Varicella	Live attenuated virus	0, 4-8 weeks	SQ	None
VACCINES FOR CERTAIN DESTINATIONS
Yellow fever	Live attenuated 17D virus	Single dose	SQ	10 years for special-risk persons; the majority of travelers are considered to have lifelong protection from one dose
Meningococcus	Quadrivalent conjugated polysaccharide (A, C, Y, W135)	Single dose	IM	5 years
Rabies	Inactivated viral cell culture	0, 7, 21-28 days	IM ^†	None routinely but two doses after each exposure
Rabies	Inactivated viral cell culture	0, 7 days per WHO ^♯	IM ^†	None routinely but two doses after each exposure
Japanese encephalitis (Vero cell)	Inactivated viral	0, 28 days	IM	1 year if at continued risk; no data on subsequent doses
Japanese encephalitis (Vero cell)	Inactivated viral	A: 0, 7 days	IM	1 year if at continued risk; no data on subsequent doses
Polio ^§	Inactivated viral	Single dose if adequate childhood series	SQ; IM acceptable	None
Cholera	Live attenuated bacteria (CVD 103-HgR)	Single dose	Oral	3 months
Cholera	Killed bacteria + recombinant B toxin subunit	0, 1 week	Oral	2 years for cholera; 3 months for ETEC

A = accelerated regimen to be used for imminent departures; ETEC = enterotoxigenic E. coli; IM = intramuscular; SQ = subcutaneous.

∗ Regimen not approved by the U.S. Food and Drug Administration for monovalent hepatitis B vaccine but approved for combination hepatitis A/B vaccine containing the same quantity of hepatitis B antigen.

♯ In the United States, the Advisory Committee on Immunization Practices considers a two-dose pre-exposure regimen to provide boostability up to 3 years, and a third dose administered from day 21 up to 3 years provides long-term boostability. An alternate option is to check the rabies antibody titer at 1 to 3 years after the 2-dose series. Long-term boostability is established if the titer is high.

† Intradermal rabies preexposure vaccine is no longer produced, and the intramuscular 1.0-mL vials are not licensed for intradermal use in a 0.1-mL dose.

§ Oral polio vaccine is no longer produced or used.

Verification and Update of Routine Immunizations

Because of the increased prevalence of many infections worldwide, routine adult immunizations ( Chapter 15 ) must be current. If no adult doses of tetanus/diphtheria/acellular pertussis (Tdap) have ever been given, a dose of Tdap should be given regardless of the time elapsed since the last tetanus/diphtheria vaccination. Persons born in the United States before 1957 or born anytime in the developing world are considered immune to measles. Other adult travelers should have received at least two doses of live measles–containing vaccine during their life unless a history of measles infection can be documented. Unvaccinated persons who meet the accepted routine indications for influenza or pneumococcal vaccines ( Chapter 15 ) should receive these vaccines during the pretravel consultation. Two doses of varicella vaccine spaced by at least 4 weeks should be considered for adult travelers without evidence of varicella immunity, but adults born before 1980 in the United States are considered immune.

Vaccines to Consider for All Developing World Travelers

A number of additional vaccines should be administered depending on the travel destinations.

Hepatitis A

Vaccination against hepatitis A ( Chapter 134 ) is indicated for every nonimmune traveler to countries or areas with moderate to high risk of infection, which includes essentially any country other than the United States, Canada, Japan, Australia, New Zealand, Scandinavian countries, and developed countries in Europe. Because outbreaks also occur in developed countries, the vaccine is beneficial for all persons and has been incorporated into the routine childhood immunization schedule in the United States. A single dose of hepatitis A vaccine given any time before travel provides adequate protection. Persons with a history of hepatitis or who previously lived in an endemic country for a prolonged period may benefit from prevaccination serum antibody testing.

Hepatitis B

Pretravel hepatitis B vaccination ( Chapter 134 ) is indicated for all nonvaccinated travelers with standard indications, such as health care providers, and all longer-stay travelers who will be visiting or residing in high- or moderate-risk areas. Transmission by routes such as sexual contact, blood transfusions, contaminated medical equipment, body piercing, tattooing, acupuncture, and sharing of bathroom facilities is difficult to control or to predict in the context of travel. Vaccination is advocated for some short-term travelers, especially younger travelers and travelers who anticipate being in close contact with local populations, even if they have no specific risk factors. Adventure travelers (accident prone), backpackers, and travelers with underlying medical conditions are more likely to require contact with the medical system. Accelerated and hyperaccelerated schedules (see Table 265-2 ), which are used widely in practice and are approved in many countries, are helpful in administering all three primary doses necessary for high assurance of protection in the frequent circumstance in which the traveler is leaving in a very short time and is at risk of exposure to hepatitis B. An adjuvanted two-dose hepatitis B vaccine with a 1-month interval produces excellent rapid response.

Combination Hepatitis A and Hepatitis B Vaccine

The combined hepatitis A and hepatitis B vaccine provides convenience for travelers who have indications for both vaccines. An accelerated 3-week schedule (see Table 265-2 ) is approved by the U.S. Food and Drug Administration.

Typhoid

Vaccination against typhoid ( Chapter 284 ) is indicated for all travelers to the Indian subcontinent and should be considered for individuals who are traveling to other endemic areas under all but the most deluxe and protected of conditions. The risk increases with duration of the trip, lodging and eating with local residents, and extent of travel beyond the usual tourist itineraries. Current typhoid vaccines do not protect against Salmonella paratyphi , which is emerging in many areas. Adherence to the oral vaccine regimen may be as low as 70%.

Influenza

Influenza ( Chapter 332 ) is transmitted year-round in the tropics and is the most common vaccine-preventable illness in travelers. An increased risk of influenza also is reported among cruise ship passengers. All travelers to the tropics or to destinations where influenza virus is currently circulating should strongly consider influenza vaccination, even if they are not otherwise at high risk.

Vaccines for Certain Destinations

Yellow Fever

The primary indication for vaccination against yellow fever ( Chapter 351 ) is to prevent infection in individuals who are traveling to high-risk areas (see www.cdc.gov/travel ), but a number of African countries and one in South America (French Guiana) require proof of yellow fever vaccination from all arriving travelers. Country-specific yellow fever entry requirements can be found at www.who.int/ith/chapters/en/index.html . In general, all healthy adult travelers to areas with a risk of yellow fever transmission should be vaccinated. Neither yellow fever vaccine nor any other vaccine is currently required for readmission to the United States. The true duration of immunity from yellow fever vaccination appears to be much longer than 10 years and may exceed 30 years.

Meningococcus

Vaccination against meningococcal infection ( Chapter 274 ) is recommended for travelers to Africa’s sub-Saharan “meningitis belt” during the dry season from December through June, especially if prolonged contact with the local populace is likely. Out-of-season epidemics also have occurred in Ethiopia, Somalia, and Tanzania. Muslims undertaking Hajj and Umrah pilgrimages in Saudi Arabia are at a higher risk of meningococcal disease ( Chapter 274 ), and proof of vaccination with the quadrivalent vaccine within the past 3 years (for polysaccharide vaccine) or 5 years (for conjugate vaccine) is required to obtain pilgrimage visas. Polysaccharide vaccine is no longer produced in Western countries.

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