According to the World Tourism Organization, international tourist arrivals grew exponentially from 25 million in 1950 to >900 million in 2008. Not only are more people traveling; travelers are seeking more exotic and remote destinations. Travel from industrialized to developing regions has been increasing, with Asia and the Pacific, Africa, and the Middle East now emerging destinations. Figure 123-1 summarizes the monthly incidence of health problems during travel in developing countries. Studies show that 50–75% of short-term travelers to the tropics or subtropics report some health impairment. Most of these health problems are minor: only 5% require medical attention, and <1% require hospitalization. Although infectious agents contribute substantially to morbidity among travelers, these pathogens account for only ∼1% of deaths in this population. Cardiovascular disease and injuries are the most frequent causes of death among travelers from the United States, accounting for 49% and 22% of deaths, respectively. Age-specific rates of death due to cardiovascular disease are similar among travelers and nontravelers. In contrast, rates of death due to injury (the majority from motor vehicle, drowning, or aircraft accidents) are several times higher among travelers. If one excludes mortality due to cardiovascular disease and preexisting illness, motor vehicle accidents account for >40% of the remaining deaths.
Incidence rate, per month, of health problems during a stay in developing countries. PCV, Peace Corps volunteer. (From Steffen R, Lobel HO: Epidemiologic basis for the practice of travel medicine. J Wilderness Med 5:56, 1994. Reprinted with permission from Chapman and Hall, New York.)
Health maintenance recommendations are based not only on the traveler's destination but also on assessment of risk, which is determined by such variables as health status, specific itinerary, purpose of travel, season, and lifestyle during travel. Detailed information regarding country-specific risks and recommendations may be obtained from the Centers for Disease Control and Prevention (CDC) publication Health Information for International Travel (available at wwwnc.cdc.gov/travel/).
Fitness for travel is an issue of growing concern in view of the increased numbers of elderly and chronically ill individuals journeying to exotic destinations (see "Travel and Special Hosts," below). Since most commercial aircraft are pressurized to 2500 m (8000 ft) above sea level (corresponding to a Pao2 of ∼55 mmHg), individuals with serious cardiopulmonary problems or anemia should be evaluated before travel. In addition, those who have recently had surgery, a myocardial infarction, a cerebrovascular accident, or a deep vein thrombosis may be at high risk for adverse events during flight. A summary of current recommendations regarding fitness to fly has been published by the Aerospace Medical Association Air Transport Medicine Committee (www.asma.org/publications/). A pretravel health assessment may be advisable for individuals considering particularly adventurous recreational activities, such as mountain climbing and scuba diving.
Immunizations for travel fall into three broad categories: routine (childhood/adult boosters that are necessary regardless of travel), required (immunizations that are mandated by international regulations for entry into certain areas or for border crossings), and recommended (immunizations that are desirable because of travel-related risks). Required and recommended vaccines commonly given to travelers are listed in Table 123-1.
Table 123–1. Vaccines Commonly Used for Travel
| Save Table
Table 123–1. Vaccines Commonly Used for Travel
|Vaccine||Primary Series||Booster Interval|
|Cholera, live oral (CVD 103 - HgR)||1 dose||6 months|
|Hepatitis A (Havrix), 1440 enzyme immunoassay U/mL||2 doses, 6–12 months apart, IM||None required|
|Hepatitis A (VAQTA, AVAXIM, EPAXAL)||2 doses, 6–12 months apart, IM||None required|
|Hepatitis A/B combined (Twinrix)||3 doses at 0, 1, and 6–12 months or 0, 7, and 21 days plus booster at 1 year, IM||None required except 12 months (once only, for accelerated schedule)|
|Hepatitis B (Engerix B): accelerated schedule||3 doses at 0, 1, and 2 months or 0, 7, and 21 days plus booster at 1 year, IM||12 months, once only|
|Hepatitis B (Engerix B or Recombivax): standard schedule||3 doses at 0, 1, and 6 months, IM||None required|
|Immune globulin (hepatitis A prevention)||1 dose IM||Intervals of 3–5 months, depending on initial dose|
|Japanese encephalitis (JE-VAX)||3 doses, 1 week apart, SC||12–18 months (first booster), then 4 years|
|Japanese encephalitis (Ixiaro)||2 doses, 1 month apart, SC||Optimal booster schedule not yet determined|
|Meningococcus, quadrivalent [Menimmune
(polysaccharide), Menactra, Menveo (conjugate)]||1 dose SC||>3 years (optimal booster schedule not yet determined)|
|Rabies (HDCV), rabies vaccine absorbed (RVA), or purified chick embryo cell vaccine (PCEC)||3 doses at 0, 7, and 21 or 28 days, IM||None required except with exposure|
|Typhoid Ty21a, oral live attenuated (Vivotif)||1 capsule every other day × 4 doses||5 years|
|Typhoid Vi capsular polysaccharide, injectable (Typhim Vi)||1 dose IM||2 years|
|Yellow fever||1 dose SC||10 years|
Diphtheria, Tetanus, and Polio
Diphtheria (Chap. 138) continues to be a problem worldwide. Large outbreaks have occurred in countries that have reduced their public vaccination programs. Serologic surveys show that tetanus (Chap. 140) antitoxin is lacking in many North Americans, especially in women over the age of 50. The risk of polio (Chap. 191) to the international traveler is extremely low, and wild-type poliovirus has been eradicated from the Western Hemisphere and Europe. However, studies in the United States suggest that 12% of adult travelers are unprotected against at least one poliovirus serogroup. Foreign travel offers an ideal opportunity to have these immunizations updated. With the recent increase in pertussis among adults, the diphtheria–tetanus–acellular pertussis (Tdap) combination is now recommended for adults as a once-only replacement for the 10-year Td booster.
Measles (rubeola) continues to be a major cause of morbidity and death in the developing world (Chap. 192). ...