Travel clinic statistics show how pre-travel care and post-travel surveillance fit together. GeoSentinel tracks patients with travel-related illness or migrant screening at sentinel clinics, while Global TravEpiNet describes people who sought pre-travel care at participating U.S. clinics. These figures are not prevalence estimates for every traveler; each percentage retains its study’s denominator, geography, and measurement period.
Contents
- Travel clinic network scale and volume
- Who appears in travel clinic surveillance
- Vaccination recommendations and uptake
- Last-minute and pediatric visits
- Diagnoses among returning travelers
- Student traveler outcomes
Travel clinic network scale and volume
The GeoSentinel Network provides a large international platform for observing travel-related illness, but it is a sentinel-clinic system rather than a survey of all travelers. As of December 2021, the network comprised 71 sites in 29 countries across six continents. It also had 164 affiliate members reporting sentinel or unusual travel-medicine cases. These counts describe the network’s reporting structure at that date, not the number of clinics worldwide. (Travel-Related Diagnoses Among U.S. Nonmigrant Travelers or Migrants Presenting to U.S. GeoSentinel Sites — GeoSentinel Network, 2012–2021)
The U.S. analysis from that source covered 20 participating U.S. sites from 2012–2021. Its dataset included 13,986 migrants with at least one confirmed or probable travel-related diagnosis and 11,987 returning U.S. nonmigrant travelers with at least one confirmed or probable travel-related diagnosis. Those totals are records meeting the study’s diagnostic criteria, not a count of every person who visited a travel clinic during the decade.
An earlier GeoSentinel report covering 2007–2011 adds an important care-seeking measure: only 40.5% of ill returned travelers reported a pre-travel medical visit. The statistic describes that earlier cohort and should not be read as a current estimate for all travelers. (GeoSentinel Surveillance of Illness in Returned Travelers, 2007–2011)
Who appears in travel clinic surveillance
The 2012–2021 U.S. nonmigrant analysis provides detail about returning travelers with available demographic and care information. Among 9,859 returning U.S. nonmigrant travelers, 55.7% were female. Among the same group, 75.3% were born in the United States. The median age was 37 years, with ages ranging from under 19 to 96 years. Travelers aged 19–39 made up 44.1% of returning U.S. nonmigrant travelers with age information.
Pre-travel preparation was not recorded for everyone. Among 8,967 returning U.S. nonmigrant travelers with information available, 65.6% had not received pre-travel health information. Among 5,884 travelers with severity information, 90.6% were seen as outpatients. For migrants with pre-travel encounter information, 88.8% had no recorded pre-travel encounter. The denominators differ, so these figures should be compared as separate measures rather than combined.
| Measure | Group and period | Result |
|---|---|---|
| Female travelers | 9,859 returning U.S. nonmigrants, 2012–2021 | 55.7% |
| Born in the United States | Returning U.S. nonmigrants, 2012–2021 | 75.3% |
| Age 19–39 | Returning U.S. nonmigrants with age information, 2012–2021 | 44.1% |
| No pre-travel health information | 8,967 returning U.S. nonmigrants, 2012–2021 | 65.6% |
| Outpatient care | 5,884 returning U.S. nonmigrants with severity information, 2012–2021 | 90.6% |
These surveillance populations are shaped by who becomes ill, seeks care, or meets a study’s inclusion criteria. They should not be treated as a demographic profile of international travelers in general. (Travel-Related Diagnoses Among U.S. Nonmigrant Travelers or Migrants Presenting to U.S. GeoSentinel Sites — GeoSentinel Network, 2012–2021)
Vaccination recommendations and uptake
Global TravEpiNet clinics saw 24,478 international travelers for pre-travel health consultation from July 1, 2012, through June 30, 2014. Of those travelers, 23,786, or 97%, were eligible for at least one of nine vaccines studied. Eligible travelers had a median of three vaccines indicated, with a range of two to four.
The most frequently recommended vaccines in this analysis were typhoid for 20,092 eligible travelers, hepatitis A for 12,990, and influenza for 10,539. Recommendation counts are counts of eligible travelers for each vaccine; they are not mutually exclusive because one traveler could have several vaccines indicated.
A total of 6,573 travelers, or 28% of vaccine-eligible travelers, refused one or more recommended vaccines. Refusal varied by vaccine. Meningococcal vaccine had a 44% refusal rate among 5,029 eligible travelers, and rabies vaccine had a 44% refusal rate among 2,650 eligible travelers. Japanese encephalitis vaccine had a 41% refusal rate among 1,846 eligible travelers.
These results describe recommendations and refusals recorded at participating clinics during the stated period. They do not establish why an individual declined a vaccine, and they are not a present-day uptake estimate. (Refusal of recommended travel-related vaccines among U.S. international travellers in Global TravEpiNet)
Last-minute and pediatric visits
Timing matters in pre-travel care. Among 76,281 Global TravEpiNet travelers, 12,494, or 16%, met the study definition of a last-minute traveler. The source reports several differences between last-minute and non-last-minute travelers. Business travel was reported by 26% of last-minute travelers versus 16% of non-last-minute travelers. Visiting friends and relatives was reported by 15% versus 8%, respectively. Trips lasting at least 29 days were planned by 27% of last-minute travelers versus 21% of non-last-minute travelers. Exclusive travel to urban destinations was reported by 40% of last-minute travelers versus 29% of non-last-minute travelers.
Only 17 last-minute travelers, or 0.1%, had pre-existing immunity to all indicated vaccines. Among 12,477 last-minute travelers without immunity to all indicated vaccines, 2,278, or 18%, had at least one vaccine deferred because there was insufficient time. Among non-last-minute travelers without immunity to all indicated vaccines, 6.5% had at least one vaccine deferred for insufficient time. Japanese encephalitis vaccine was indicated for 1,004 last-minute travelers; 526, or 52%, did not receive it because there was insufficient time to complete the series. The study period is reported in the source without a calendar date in the supplied record. (Characteristics and preparation of the last-minute traveler: analysis of vaccine usage in the Global TravEpiNet Consortium)
Pediatric travelers represented a defined share of pre-travel visits in another Global TravEpiNet analysis. Children under 18 accounted for 3,332, or 10%, of 32,099 travelers seeking pre-travel healthcare at 19 GTEN clinics from January 1, 2009, through June 6, 2012. (Pre-Travel Health Preparation of Pediatric International Travelers: Analysis From the Global TravEpiNet Consortium)
Diagnoses among returning travelers
Among returning U.S. nonmigrant travelers in the GeoSentinel analysis from 2012–2021, gastrointestinal diagnoses accounted for 43.2% of 11,987 travel-related diagnoses. Febrile diagnoses accounted for 16.7%, respiratory or ear, nose, and throat diagnoses for 13.0%, and dermatological diagnoses for 8.9%.
Acute diarrhea accounted for 16.9% of all travel-related diagnoses, while malaria accounted for 3.5%. Four deaths were reported among returning U.S. nonmigrant travelers, including two patients with severe Plasmodium falciparum malaria. These are observed diagnoses and outcomes in the GeoSentinel dataset, not risks for an average traveler.
The category-level results also show how broad groups contain more specific conditions. Acute diarrhea represented 39.3% of 5,173 gastrointestinal diagnoses. Viral syndrome represented 29.0% of 2,001 febrile diagnoses. Because the source reports both broad categories and their subcategories, the percentages should not be added together as if they were separate, non-overlapping populations. (Travel-Related Diagnoses Among U.S. Nonmigrant Travelers or Migrants Presenting to U.S. GeoSentinel Sites — GeoSentinel Network, 2012–2021)
Student traveler outcomes
A GeoSentinel analysis of illness among U.S. resident student travelers included 432 students aged 17–24 with confirmed travel-related illness from 2007–2017. The median age was 21 years, and female students represented 69% of the ill student-traveler cohort. More than 70% had a pre-travel consultation.
Sub-Saharan Africa was the most common exposure region, accounting for 112 students, or 26%. India was the most common individual exposure country, accounting for 44 students, or 11%. The median duration of travel abroad was 40 days, with a range of 1–469 days.
Gastrointestinal illness was the most common diagnosis category, accounting for 45% of 581 confirmed diagnoses. The number of confirmed diagnoses exceeds the number of students because the analysis could record more than one diagnosis for a traveler. The student results therefore describe ill students presenting within GeoSentinel surveillance, not all students who traveled abroad. (Illness among US resident student travellers after return to the USA: a GeoSentinel analysis, 2007–17)
Across these studies, travel clinic statistics describe several linked but distinct stages: preparation before departure, delayed or last-minute vaccination, and clinical evaluation after return. The figures are most useful when read with their source, denominator, geography, and period intact. They are descriptive surveillance and clinic-care statistics, not personal medical advice.