Data from 15,440 travelers were collected from March 1, 2008, to July 31, 2010, including traveler demographic characteristics, trip characteristics, medical history, and vaccinations, medications, and travel medicine advice given at the pretravel visit. Demographic information included age, sex, race/ethnicity, country of origin, year of arrival in the United States, parents' countries of origin, and primary language. Trip characteristics included destination countries, departure and return dates, purpose of travel, and type of accommodations. Travel medicine physicians documented advice, but templates used to collect these data differed by clinic. Detailed analyses of pediatric VFR travelers and those with medical comorbidities and immunocompromising conditions have been published previously.12, 13

The BATMN clinics have different traveler populations. Clinics A and B are based at urban teaching hospitals, but Clinic B has a broad patient base that includes a substantial proportion of minorities, recent immigrants, and refugees. Clinic C, at a suburban university-affiliated hospital, serves many multinational corporations whose employees travel frequently. Clinic D, another teaching hospital, has a broad patient population. Clinic E is in Boston's Chinatown at an academic medical center. Clinics B, C, and E provide services for travelers of all ages; Clinic A sees only adults (≥18 years), and Clinic D sees adults and older children. Physicians direct each clinic. Staff providing pretravel consultation vary by clinic and include nurses, nurse practitioners, and physicians. The institutional review boards of all sites reviewed and approved the study procedures. The study was approved by the institutional review boards of all participating institutions and of the CDC. A waiver of informed consent was provided, given the minimal risk to participants of having their de-identified data extracted from the medical record.

Anonymized individual traveler data were extracted from paper medical records for 4 sites and downloaded from electronic medical records from Clinic B. Data from paper records were entered into an electronic database (CSPro, version 4.0; US Census Bureau) and merged with the downloaded electronic medical record data.

Data were analyzed using SAS software, version 9.4 (SAS Institute). We used the χ² test to compare frequencies and the Wilcoxon rank sum test to compare continuous variables. We report frequencies for categorical demographic variables and median and range or interquartile range (IQR) for continuous demographic variables. The United Nations Statistics Division list of countries and regions was used to categorize geographical regions and subregions.¹⁴ Malaria (total/partial/none) risk destination and yellow fever (YF) risk (classified as holoendemic/partially endemic/none) countries were assigned according to CDC classifications, corresponding to our study period.¹⁵ Countries with typhoid fever risk were categorized as high (>100 annual cases per 100,000 person-years), medium (10-100 annual cases per 100,000 person-years), and low (<10 annual cases per 100,000 person-years) incidence.¹⁶ For purposes of analysis, only total malaria, holoendemic YF, and high typhoid risk countries were considered at-risk destinations. To assess vaccination practices, we selected specific countries at high risk for certain vaccine-preventable diseases (India, typhoid; Ghana, YF; Nigeria, polio; and China, influenza) and then quantified the proportion of travelers who were up-to-date with or received the relevant vaccinations. For the analysis of counseling, missing responses were recorded as not done.

The median age of the 15,440 travelers was 34 years (IQR, 24-51 years); 1731 (11.2%) were aged 18 years or younger (Table 1). More travelers were female (8730 of 15,439 [56.5%]), 72.4% (10,528 of 14,545) were white, and for 86.8% (12,314 of 14,180), English was the primary language. There were notable differences across sites. A greater proportion of travelers seen at Clinic B were black and Hispanic, and more Clinic E travelers were Asian. Almost 40% (893 of 2296 [38.9%]) of Clinic B travelers and 30.7% (250 of 815) of Clinic E travelers were born outside the United States, and 19.5% (490 of 2512), 17.1% (1141 of 6668), and 13.5% (141 of 1044) of those seen at Clinics B, D, and E, respectively, were not native English speakers. Roughly a fifth of travelers seen at Clinics B and E were aged 18 years or younger; pediatric patients were seen less frequently at the other BATMN clinics. Clinic C travelers tended to be older; 14.3% (201 of 1403) were 65 years or older. In contrast, Clinic A provided pretravel services for a predominantly white, young and middle-aged adult population.Table 1

Demographic and Trip Characteristics of Travelers Seen at Boston Area Travel Medicine Clinics Before Trip Departure (March 2008-July 2010), Stratified by Clinica^,b

Purpose of travel was tourism for 55.5% (8251 of 15,360) and VFR for 18.7% (2876 of 15,360; range, 7.6% [184 of 2436] to 39.0% [1029 of 2639]). Clinics B and E had a large proportion of VFR travelers (39.0% [1029 of 2639] and 24.1% [415 of 1725], respectively), and more Clinic B travelers were traveling for research/education (411 of 2639 [15.6%]). Clinics B and E had fewer business travelers relative to the other sites. Travelers were seen a median of 23 days before travel (IQR, 12-40 days); 29.4% (3077 of 10,483) were seen less than 2 weeks before departure, including 12.3% (1293 of 10,483) who were seen within a week and 2.7% (283 of 10,483) within 2 days before departure (although at Clinic C, 119 of 1368 travelers [8.7%] were seen within 2 days of travel). Median trip duration was 15 days (IQR, 10-29 days) but was significantly longer at Clinic B (21 days) relative to other sites (P<.001). Most travelers planned to stay in a hotel, home, or hostel, although proportions varied widely; 7.9% (1269 of 16,115) anticipated staying in tents.

The top 10 destinations were India, China, South Africa, Tanzania, Peru, Kenya, Thailand, Vietnam, Costa Rica, and Brazil (Figure 1). Business travelers more commonly visited India and China. The VFR travelers visited, in order of frequency, Vietnam, Brazil, India, Haiti, Kenya, and China. Clinic B had 3 African countries (Nigeria, Kenya, and Ghana) among its top 5 destinations (Table 2), while Clinic E had a greater proportion of travelers to Asia (India, China, Vietnam, and Thailand).Figure 1

Top 10 most frequent destinations reported by Boston-area international travelers from 2008 to 2010, stratified by purpose of travel.

In all clinics, more women than men traveled for research/education or missionary/volunteer work (69% vs 31%, P<.001; and 65% vs 35%, P<.001, respectively), whereas more business travelers were male (59%, P<.001) (Table 3). Research/education and missionary/volunteer travelers were younger than business travelers (median ages, 22 and 27 years vs 40 years). More VFR travelers were black (P<.001), Asian (P<.001), or Hispanic (P<.001) than white, compared with those traveling for other reasons. Median interval until departure was shortest among VFR and business travelers (19 and 18 days, respectively) and longest for research/education travelers (29 days). Research/education travelers also had the longest median trip duration (33.5 days). The VFR travelers were more likely to stay at a home or local residence (2196 of 2976 [73.8%]; P<.001) compared with other travelers.Table 3

Demographic and Trip Characteristics for Travelers Attending Boston Area Travel Medicine Clinics Before Departure (March 2008-July 2010), Stratified by Purpose of Travela^,b

Travel to malaria risk countries varied by clinic, ranging from 23.7% (333 of 1403) for Clinic C to 52.0% (1306 of 2512) for Clinic B (Table 2). Clinic B travelers were also more likely to travel to YF risk countries (47.6% [1196 of 2512]) compared with travelers at other clinics (24.5% [344 of 1403] to 32.8% [521 of 1588]; P<.001). The proportions of travelers to areas with typhoid risk ranged from 8.0% (156 of 2512) to 16.3% (228 of 1403).

Prescriptions for traveler's diarrhea (TD) self-treatment medications were given to 13,261 of the 15,440 travelers (85.9%); 285 travelers received more than one prescription. Adults were prescribed TD self-treatment more frequently than children (87.7% [12,187 of 13,895] vs 69.5% [1074 of 1545]; P<.001), and proportions given TD prescriptions varied by destination and clinic. Travelers received TD self-treatment more frequently for trips to Oceania, Eastern Europe, and Asia (92% [5146 of 5591]) to 96.8% [153 of 158] than Africa (81.4% [4344 of 5377]). Ciprofloxacin was prescribed most frequently (60.0% [9239 of 15,400]), followed by azithromycin (30.6% [4710 of 15,403]), levofloxacin (4.1% [492 of 12,124]), and rifaximin (0.2% [24 of 10,563]). Azithromycin was prescribed more frequently than ciprofloxacin for travelers to Asia (Figure 2). Of 1602 children, 1160 (72.4%) received an antibiotic for TD, 105 of whom (9.1%) were prescribed a fluoroquinolone.Figure 2

Proportion of antibiotics for self-treatment of traveler's diarrhea prescribed by Boston Area Travel Medicine Network clinics from 2008 to 2010, stratified by region.

Of the 2080 travelers to India, 1979 (95.1%; range, 78.3% [141 of 180] to 98.1% [471 of 480]) were immunized against typhoid, and 473 of 520 travelers to Ghana (91.0%; range, 73.4% [91 of 124] to 97.7% [215 of 220]) were given YF vaccine (Table 4). Use of influenza vaccine (during the visit or current influenza season) for travelers to China varied widely, ranging from 4.4% (4 of 91) to 65.7% (132 of 201). Although most travelers to Nigeria were given a polio booster, a lower percentage at Clinic B received this vaccine (69.4% [102 of 147] vs 82.0% [41 of 50] to 100% [47 of 47 and 6 of 6] at the other clinics).Table 4

Pretravel Vaccinations for Specific High-Risk Locations Among Travelers Seen at Boston Area Travel Medicine Clinics Before Trip Departure (March 2008-July 2010)a

Advice on preventing TD, malaria, and other vector-borne diseases was usually provided to travelers at all clinics (13,397 of 13,580 [98.7%], 11,551 of 13,579 [85.1%], and 11,307 of 11,656 [97.0%], respectively) (Supplemental Table, available online at http://www.mcpiqojournal.org). Counseling on animal bite prevention and management of potential rabies exposure varied from 55.9% (780 of 1395) to 92.7% (1962 of 2116). Greater variability existed in provision of advice on preventing sexually transmitted infections (12.8% [179 of 1396] to 84.1% [5595 of 6655] between Clinics C and D, respectively).