The VFR Traveler

The term VFR usually describes an immigrant, ethnically and racially distinct from the majority population of the country of residence (usually a higher-income country), who returns to his/her homeland (lower-income country) to Visit Friends or Relatives (1-3). VFRs also may include the spouse and children who were born in the country of residence. Migration patterns to North America have changed over the past 30 years, and many immigrants now come from Asia and Latin America, with increasing numbers from Africa (4); previously the predominant source of immigrants was Europe. Immigrants from developing countries have become an increasingly important group of travelers for two reasons. First, there are far more immigrants and therefore VFR travelers than ever before. In 2004, 12% of the U.S. population was foreign born (5) and over 40% of U.S. residents traveling overseas listed VFR as a reason for travel (6). Second, VFRs experience a higher incidence of travel-related infectious diseases, such as malaria, typhoid fever, tuberculosis, and hepatitis A, than do other groups of international travelers.

Why VFRs Are At Increased Risk for Travel-Related Infections

In 2004, 53% of imported malaria cases in U.S. civilians occurred among VFRs (7). Data from GeoSentinel, the International Society of Travel Medicine/CDC sentinel surveillance network, show that among ill travelers, VFRs are four times more likely to acquire malaria than are tourist travelers (3). Most imported malaria cases in VFRs, documented both in Europe and North America, occur in travelers returning from sub-Saharan Africa. Partial immunity to malaria may decrease the risk of death from malaria among immigrants from endemic countries; however, immunity is not complete, and serious complications can occur, especially among children who have not previously been exposed to malaria (8).

Typhoid fever also occurs disproportionately among VFRs (3,9,10). Recent studies have shown that most typhoid fever cases in United States are imported and that 65% of these occur in VFRs, mostly from South Asia and Latin America (9). Similarly, tuberculosis (3) and hepatitis A occur more commonly among VFRs than among tourist travelers. A British study of travel-associated hepatitis A showed that VFR children younger than 15 years of age were at highest risk of infection, and surprisingly, many were symptomatic. Most cases were acquired in South Asia (11).

Several factors account for the disproportionate infectious disease risks experienced by VFRs. Several studies have documented that 30% or fewer of VFRs have pre-travel health encounters (1-3,12). Even when travel health advice is sought, adherence to recommendations is frequently poor (1,2,12). Possible barriers to obtaining and adhering to pre-travel health advice include financial limitations, language barriers, and, perhaps most importantly, health beliefs that differ from those in the country of residence (1,2). Because VFRs were often born in areas where travel-related infections are endemic, they may believe that they are immune or perceive that these infections do not cause serious illness. Even their health-care providers, who may come from the same countries as they do, may share their beliefs that the risk of these infections and their severity are low. These health beliefs likely contribute to lower rates of hepatitis A and typhoid vaccination and the infrequent use of malaria chemoprophylaxis among VFRs compared with other international travelers (13,14).

Lack of adequate pre-travel health preparation may be especially problematic for VFRs, whose travel itineraries and travel styles tend to place them at higher risk for travel-related infections than other travelers; e.g., VFRs take longer trips and travel to higher risk destinations. A recent study among ill international travelers demonstrated that VFRs were more likely than other travelers to have visited sub-Saharan Africa and more likely to have traveled for longer than 30 days (3). Further, because VFRs likely stay in the homes of family or friends when abroad, it may be more difficult to adhere to prevention recommendations, such as those regarding safe food and water and the use of screens, air conditioning, or bed nets to reduce mosquito exposure (1,14).

Pre-Travel Health Counseling for VFRs

A critical first step to ensuring good pre-travel health care for VFRs is increasing awareness among travelers and health-care professionals of VFRs’ risks for travel-related infections and barriers to travel health services. In counseling VFRs, health-care providers must first convince them that they may be at risk for serious infections, not only because of waning immunity, but also because of the ever-changing patterns of disease and drug resistance in their home countries.

Vaccinations

Travel immunization recommendations and requirements for VFRs are the same as those for U.S.-born travelers. However, because childhood immunizations vary by country, the health-care provider must establish whether the immigrant traveler has had his or her “routine” immunizations (e.g., measles, tetanus, etc.) or has a history of the diseases (15). In the absence of documentation of immunizations or other evidence of immunity, the adult traveler should be considered nonimmune, and appropriate vaccinations should be provided. Immunity to hepatitis A should not be assumed, given the relatively high proportion of adolescent and adult immigrants from developing countries who may still be susceptible (16-18). If time and costs permit, serologic testing for both hepatitis A and B may be worthwhile. Otherwise, it may be more practical to administer both vaccines. Special consideration should also be given to varicella, because immigrants from some developing regions, notably South and Southeast Asia and Latin America, may be susceptible; infection occurs at an older age in tropical areas of the world compared to temperate regions (15,19-21). Varicella infection in adults carries a much higher morbidity and mortality than in children. Clinicians should use the pre-travel consultation to ensure that travelers are not susceptible to varicella by documenting immunity or providing vaccination.

Malaria Prevention

VFR travelers to endemic areas should be reminded of the benefits of barrier methods of prevention, such as bed nets, and insect repellents, particularly for children (see Chapter 4). Posters depicting malaria prevention techniques by families of various ethnicities are available for downloading from the CDC malaria prevention website (http://www.cdc.gov/malaria/travel/index.htm) and may be used in clinics to prompt discussion. Also, there are a variety of scenarios depicting real-life stories from VFR families who were impacted by malaria that may also be useful tools in communicating risk.

Chemoprophylaxis

VFRs should be advised that older drugs such as chloroquine, proguanil, and pyrimethamine are often no longer effective. This advice is particularly important for travelers to sub-Saharan Africa, where the risk of Plasmodium falciparum malaria is high. Travelers should be encouraged to purchase their medications before traveling to ensure the quality of the drugs and to avoid conflicting advice from overseas practitioners who may not be aware of the impact of drug-resistant malaria on a traveler with waning immunity. Recent studies in Southeast Asia showed that 38%-52% of antimalarial drugs (notably the artemesinins) purchased locally were counterfeit or substandard (22).

References

1. Bacaner N, Stauffer B, Boulware DR, Walker PF, Keystone JS. Travel medicine considerations for North American immigrants visiting friends and relatives. JAMA. 2004;291:2856-64.
2. Angell SY, Cetron MS. Health disparities among travelers visiting friends and relatives abroad. Ann Intern Med. 2005;142:67-72.
3. Leder K, Tong S, Weld L, Kain KC, Wilder-Smith A, von Sonnenburg F, et al. Illness in travelers visiting friends and relatives: a review of the GeoSentinel Network. Clin Iinfect Dis. 2006;43:1185-93.
4. U.S. Department of Homeland Security. Office of Immigration Statistics. Annual Flow Report: U.S. Legal Permanent Residents: 2005. Available athttp://www.uscis.gov/graphics/shared/statistics/publications/2005NatzFlowRpt.pdf PDF document. (Accessed July 17, 2006.)
5. U.S. Census Bureau. The Foreign-Born Population in 2004. Available athttp://www.census.gov/population/pop-profile/dynamic/ForeignBorn.pdf. (Accessed July 17, 2006.)
6. U.S. Department of Commerce. Office of Travel and Tourism Industries. 2004 Profile of U.S. resident travelers visiting overseas destinations reported from: Survey of international air travelers. Available at http://tinet.ita.doc.gov/view/f-2004-101-001/index.html. (Accessed July 19, 2006.)
7. Skarbinski J, James EM, Causer LM, Barber AM, Mali S, Nguyen-Dinh P, et al. Malaria surveillance—United States, 2004. MMWR Surveill Summ. 2006;55:23-37.
8. CDC. Malaria in multiple family members—Chicago, Illinois, 2006. MMWR Morbid Mortal Wkly Rep. 2006;55:645-8.
9. Lynch M, Bulens S, Polyak C, Blanton E, Medalla F, Barrett TJ, et al.. Multi-drug resistance among Salmonella Typhi isolates in the United States, 1999-2003. Sixth International Conference on Typhoid Fever and other Salmonelloses. Guilin, China, November 12-14, 2005.
10. Steinberg EB, Bishop R, Haber P, Dempsey AF, Joekstra RM, Nelson JM, et al. Typhoid fever in travelers: who should be targeted for prevention? Clin Infect Dis. 2004;39:186-91
11. Behrens RH, Collins M, Botto B, Heptonstall J. Risk for British travellers of acquiring hepatitis A. BMJ. 1995;311:193.
12. Scolari C, Tedoldi S, Casalini C, Scarcella C, Matteelli A, Casari S, et al. Knowledge, attitudes, and practices on malaria preventive measures of migrants attending a public health clinic in northern Italy. J Travel Med. 2002;9:160-2.
13. Van Herck K, Van Damme P, Castelli F, Zuckerman J, Nothdurft H, Dahlgren AL, et al. . Knowledge, attitudes and practices in travel-related infectious diseases: the European airport survey. J Travel Med. 2004;11:3-8.
14. dos Santos CC, Anvar A, Keystone JS, Kain KC. Survey of use of malaria prevention measures by Canadians visiting India. CMAJ. 1999;160:195-200.
15. Barnett ED, Christiansen D, Figueira M. Seroprevalence of measles, rubella, and varicella in refugees. Clin Infect Dis. 2002;35:403-8.
16. Jacobsen KH, Koopman JS. Declining hepatitis A seroprevalence: a global review and analysis. Epidemiol Infect. 2004;132:1005-22.
17. Poovorawan Y, Theamboonlers A, Sinlaparatsamee S, Chaiear K, Siraprapasiri T, Khwanjaipanich S, et al. Increasing susceptibility to HAV among members of the young generation in Thailand. Asian Pac J Allergy Immunol. 2000;18:249-53.
18. Tufenkeji H. Hepatitis A shifting epidemiology in the Middle East and Africa. Vaccine. 2000;18 Suppl 1:S65-7.
19. Mandal BK, Mukherjee PP, Murphy C, Mukherjee R, Naik T. Adult susceptibility to varicella in the tropics is a rural phenomenon due to the lack of previous exposure. J Infect Dis. 1998;178 Suppl 1:S52-4.
20. Lee BW. Review of varicella zoster seroepidemiology in India and Southeast Asia. Trop Med Int Health. 1998;3:886-90.
21. Lokeshwar MR, Agrawal A, Subbarao SD, Chakraborty MS, Ram Prasad AV, Weil J, et al. Age related seroprevalence of antibodies to varicella in India. Indian Pediatr. 2000;37:714-9.
22. Newton PN, McGready R, Fernandez F, Green MD, Sunjio M, Bruneton C, et al. Manslaughter by fake artesunate in Asia-will Africa be next? PLoS Med. 2006;3:e197.

HENRY BAGGETT