We included 3,707 VFR and 17,507 non-VFR travelers in our analysis; all were traveling to an LLMI country as defined by the World Bank. Females comprised a slight majority (54%) of both VFR and non-VFR travelers seen at Global TravEpiNet sites. VFR travelers were significantly younger than non-VFR travelers (median age = 30 years versus 37 years, P < 0.001); 18% of VFR travelers were younger than 6 years of age (), whereas < 1% of non-VFR travelers were in this age category. VFR travelers pursued trips of longer duration than non-VFR travelers (median duration = 25 days versus 14 days, P < 0.001) and were more likely to visit only urban areas (42% versus 30%, P < 0.0001) (). Among travelers to Africa, VFR travelers were particularly likely to visit only urban areas (42% of VFR travelers versus 19% of non-VFR travelers to the WHO African region, P < 0.01). VFR travelers also sought pre-travel health care closer to their departure date than non-VFR travelers (median = 17 days versus 26 days prior to departure, P < 0.001) ().
Demographic and travel-related characteristics of VFR travelers compared with non-VFR travelers at Global TravEpiNet from January of 2009 to December of 2011
Overall, VFR travelers were more likely than non-VFR travelers to visit countries with regions endemic for malaria or yellow fever. For VFR travelers, the most frequently visited regions were the WHO regions of Africa (46%), Southeast Asia (26%), and the Western Pacific (18%). For non-VFR travelers to LLMI countries, Africa (31%), Southeast Asia (30%), and the Western Pacific (22%) were also the most commonly visited regions. India, Ghana, Ethiopia, Nigeria, and Vietnam were the most common destination countries for VFR travelers; aside from India, none of these countries were among the top destinations of non-VFR travelers (). VFR travel took place most frequently (29% of trips) in the summer months of the northern hemisphere.
VFR travelers had fewer existing medical condition than non-VFR travelers (). The types of medical conditions also differed between VFR and non-VFR travelers. In particular, VFR travelers were more likely to be pregnant or breastfeeding, and diabetes and immune system disorders were more common in VFR travelers than non-VFR travelers. VFR travelers were less likely to report a neuropsychiatric condition than non-VFR travelers. On average, VFR travelers were taking fewer medications than non-VFR travelers (VFR median = 0, interquartile range [IQR] = 0–1; non-VFR median = 1, IQR = 0–2; P < 0.001).
Medical conditions of VFR travelers compared with non-VFR travelers at Global TravEpiNet from January of 2009 to December of 2011
We evaluated the malaria chemoprophylaxis agent that was prescribed to travelers going to countries with regions that are endemic for malaria (). Atovaquone/proguanil was the most commonly prescribed chemoprophylaxis agent for both VFR and non-VFR travelers; however, a much higher proportion of VFR travelers than non-VFR travelers received mefloquine (30.2% versus 3.6%; P < 0.001). VFR travelers more commonly received mefloquine than non-VFR travelers when traveling for 28 days or fewer (17.5% versus 2.5%; P < 0.001) and when traveling for 7 days or fewer (12.7% versus 1.6%; P < 0.001). VFR travelers were less likely than non-VFR travelers to receive prescription antibiotics for travelers' diarrhea (72.6% versus 91.4%; P < 0.001).
Malaria chemoprophylaxis in VFR travelers compared with non-VFR travelers traveling to countries that include regions endemic for malaria
VFR travelers were more likely than non-VFR travelers to have existing immunity to hepatitis A at the time of their pre-travel consultation (47% versus 40%; P < 0.001). Typhoid, hepatitis A, and yellow fever were the three most frequently administered vaccines among VFR travelers and non-VFR travelers alike (administered to 74%, 41%, and 34% of VFR travelers, respectively, and 76%, 55%, and 26% of non-VFR travelers, respectively).
Clinicians were required to provide a reason when vaccines were not administered to travelers to whom they would be otherwise indicated by the current CDC guidelines at the time of the visit. In most (95%) cases, declination by the traveler was cited as the reason for not administering a vaccine. Referral to another provider, medical contraindication, insufficient time to complete the vaccine series before departure, and lack of availability of vaccine were other reasons that were cited less frequently (< 5%). We performed a multivariable analysis to identify predictors of declining any recommended vaccine in the study population. Being a VFR traveler (odds ratio [OR] = 1.30, 95% confidence interval [CI] = 1.15–1.48), traveling for > 28 days (OR = 1.72, 95% CI = 1.56–1.89), traveling to the WHO African region (OR = 1.21, 95% CI = 1.08–1.35), being an adult (OR = 1.54, 95% CI = 1.32–1.78), and having fewer than two medical concerns (OR = 1.23, 95% CI = 1.13–1.34) were each independently associated with declining a recommended vaccine. In particular, 10% of VFR travelers traveling to yellow fever-endemic countries who were offered the yellow fever vaccine declined it, and 85% of VFR travelers who were offered rabies vaccine declined it (). In contrast, 4% of non-VFR travelers visiting yellow fever-endemic countries who were offered the yellow fever vaccine declined it, and 59% of non-VFR travelers who were offered rabies vaccine declined it.
Figure 1. Proportion of VFR travelers and non-VFR travelers declining selected indicated vaccines at Global TravEpiNet from January of 2009 to December of 2011. The total number of individuals who were administered or declined the vaccine is shown above each column. (more ...)