VFRs: Recent Immigrants Returning 'Home' to Visit Friends and Relatives

The term VFR usually refers to an immigrant, ethnically and racially distinct from the majority population of the country of residence, who returns to his/her homeland to Visit Friends and/or Relatives. Over the past 30 years, the patterns of migration to North America have shifted; most immigrants come from Asia, Africa, and Latin America; previously the predominant source of immigrants was Europe. Immigrants from developing countries have become an increasingly important group of travellers for two reasons. First, there are far more VFRs than ever before. In 2002, 10% of the U.S. population was foreign born, and in the same year 40% of all overseas journeys made by U.S. citizens were made by VFRs. Second, disease rates in this group have been shown to be considerably higher than in native-born Americans.

VFRs appear to be at greater risk for malaria, typhoid fever, cholera, and hepatitis A. In 2002, 45% of imported malaria cases in the United States were in VFRs. Data from GeoSentinel, the International Society for Travel Medicine/CDC sentinel surveillance network, show that VFRs are eight times more likely to acquire malaria than are U.S.-born tourists. Most imported malaria cases in VFRs, documented both in Europe and North America, have been in travellers returned from sub-Saharan Africa. Because of their partial immunity, these VFRs are much less likely to die from malaria; however, in the absence of repeated malaria infections, waning immunity puts them at risk for serious complications.

Recent studies have shown that most typhoid fever cases in United States are imported and that 77% of these occur in VFRs, mostly from South Asia, Southeast Asia, and Latin America. The risk of typhoid fever during travel to South Asia has been shown to be 25% higher among foreign-born U.S. citizens. Similarly, a review of imported cholera into the United States from 1992 to 1994 showed that 78% of cases occurred among VFRs, mostly from Latin America. A British study of travel-associated hepatitis A showed that VFR children <15 years of age were at highest risk of infection, and surprisingly, many were symptomatic; most cases were acquired in South Asia.

The cause for the increased rates of infectious disease among VFRs is multifactorial and may vary among the different ethnic groups. VFRs may not seek pre-travel health advice, or they may seek advice from friends and relatives or even from physicians in their communities who may not understand the risks. In addition, VFRs may fail to use appropriate prevention measures, which may stem from living conditions abroad that include lack of control over food hygiene and water purification and inadequate protection against insects. Many VFRs believe that they will not contract infections such as malaria because they consider themselves immune.

For many VFRs newly arrived to North America or Europe, cost is one of the most important contributors to failure to obtain pre-travel health advice. This factor is particularly relevant to heads of large families who wish to return to visit their countries of origin with their children. Other barriers to pre-travel health advice include language issues, access to the health-care system, and concern over immigration status. Finally, studies have shown that primary-care physicians have not emphasised sufficiently the need for VFRs to take the same precautions as U.S.-born travellers to developing countries, failing to recognise that VFRs are at increased risk for travel-related infectious diseases, even though they grew up in countries where these diseases are commonplace and attract little attention.

In counselling VFRs, health-care providers must first convince them that they may be at risk for serious infection, not only because of waning immunity, but also because of the ever-changing patterns of disease and drug resistance in their home country. Travel immunisation requirements for VFRs are the same as those for U.S.-born travellers. However, the health-care provider should establish whether the immigrant traveller has had his or her childhood immunisations or has a history of vaccine-preventable diseases. In the absence of documentation of childhood immunisations, the adult traveller should be considered to be unimmunised, and a full series of childhood vaccinations should be provided. Several recent studies have shown that adolescent and adult immigrants from developing countries may still be susceptible to hepatitis A, particularly if they have been living in the middle or upper end of the socioeconomic scale before immigrating to the United States. 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. Immigrants from some developing regions of the world, notably Southeast Asia and Latin America, may also be susceptible to varicella, because this infection occurs at an older age in these areas. In the United States, approximately 90% of children will have had varicella vaccine or infection with chickenpox by the age of 10; at the same age, only 40%-60% of children in these regions are immune to this infection. Varicella infection in adults carries a much higher morbidity and mortality than when it occurs in children. Using the pre-travel consultation to ensure that travellers are not susceptible to varicella by documenting immunity or providing vaccination is an important way of preventing future serious illness.

With respect to malaria 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 travellers to sub-Saharan Africa, where the risk of Plasmodium falciparum malaria is high. Travellers should be encouraged to purchase their medications in North America, where the quality of the drugs can be assured, and to avoid obtaining conflicting advice from overseas practitioners who may not be aware of the impact of drug-resistant malaria on a traveller with waning immunity. One recent study in Southeast Asia showed that 38% of antimalarial drugs purchased locally were counterfeit or substandard.

Bibliography
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  • Barnett ED, Christiansen D, Figueira M. Seroprevalence of measles, rubella, and varicella in refugees. Clin Infect Dis. 2002;35:403-8.
  • Behrens RH, Collins M, Botto B, et al. Risk for British travellers of acquiring hepatitis A. BMJ. 1995;311:193.
  • Schlagenhauf P, Steffen R, Loutan L. Migrants as a major risk group for imported malaria in European countries. J Travel Med. 2003;10:106-7.
  • Steinberg EB, Bishop R, Haber P, et al. Typhoid fever in travellers: who should be targeted for prevention? Clin Infect Dis. 2004;39:186-91

- Jay Keystone

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