Travel health statistics show how prevention, surveillance, and destination-specific risks shape safer international travel. CDC data range from more than 1 billion annual visits to U.S. airports to detailed schedules for measles, rabies, polio, and other vaccines. The figures below identify the source and measurement period for each statistic so travelers can distinguish current guidance, historical counts, and global estimates.
Contents
- How CDC monitors travelers
- Travel health notices and public information
- Malaria statistics and imported infections
- Dengue, chikungunya, and mosquito-borne risk
- Vaccination timing and protection
- Rabies, polio, and hepatitis B schedules
How CDC monitors travelers
The scale of international movement is one reason traveler-based surveillance matters. The CDC Traveler-Based Genomic Surveillance program reports that U.S. airports are visited by more than 1 billion travelers each year. That figure describes annual airport visitation, not the number of unique people or the number of international arrivals.
CDC’s Traveler-Based Genomic Surveillance, or TGS, uses voluntary and anonymous sampling from arriving international air travelers at select U.S. airports. The program has surpassed 1 million voluntary participants, according to a CDC media release. CDC has also analyzed more than 2,600 airplane wastewater samples as part of its biosurveillance efforts.
The sampling process has several stages:
- Each participating traveler provides 2 nasal swab samples.
- One swab is pooled with samples from other travelers before testing.
- If a pooled sample is positive by RT-PCR, CDC tests the individual samples.
- Individual positive samples are sequenced to identify variants, strains, or mutations of public health importance.
CDC says this approach can provide information about transmissibility, virulence, and how a pathogen may respond to current treatments or vaccines. TGS data are updated weekly on Friday by 1 p.m. Eastern Time, according to the CDC Traveler-Based Genomic Surveillance Data.
These are surveillance measurements rather than a count of every infection among travelers. The voluntary design and select-airport coverage are important context when interpreting the results.
Travel health notices and public information
Travel information is also measured by the volume of public guidance. CDC’s Travelers’ Health website received more than 19 million views in 2025, according to the CDC FY 2027 budget. That is a website-view count for 2025, not a count of travelers or consultations.
CDC’s FY 2026 budget request for Travel and Port Health Protection was $79,772,000. Budget requests describe requested funding, not necessarily final spending or program results.
CDC posted more than 1,000 Travel Health Notices between January 2020 and June 2021, according to the CDC FY 2024 budget request. CDC says Travel Health Notices can address four situations: disease outbreaks, sporadic cases in unusual locations, natural or human-made disasters, and mass gatherings. The notice count covers that specific January 2020–June 2021 period and should not be read as a current annual rate.
Malaria statistics and imported infections
Malaria remains a major travel-related concern because the U.S. burden is largely connected to infections acquired elsewhere. The CDC Yellow Book malaria chapter says almost all of the approximately 2,000 malaria cases occurring each year in the United States are imported.
CDC reported 2,048 malaria cases in the United States and its territories in 2019, compared with 602 cases in 2020. These are reported case counts for the stated years, not an estimate of annual cases across all years. CDC also reported 10 locally acquired mosquito-transmitted malaria cases from four states in 2023.
For 2019 cases with a known country of acquisition, the geographic distribution was concentrated in Africa. The CDC Yellow Book reports that 93% were acquired in Africa, 4% in Asia, 2% in the Caribbean and the Americas, and less than 1% in Oceania and the Middle East.
Among U.S. civilians with malaria who reported a reason for travel, 76% were visiting friends and relatives. This statistic describes the travel-reason subgroup in the cited CDC material; it does not mean that 76% of all travelers face malaria or that visiting friends and relatives is the only relevant travel pattern.
The global context is much larger. The CDC Yellow Book, citing the WHO 2024 malaria report, says 83 countries reported about 263 million malaria infections in 2023 and 597,000 malaria deaths in 2023. Those are global 2023 estimates or reported totals as presented in the WHO report, not U.S. travel cases.
Dengue, chikungunya, and mosquito-borne risk
Dengue is another important travel-health statistic because exposure is widespread in tropical and subtropical settings. The CDC Yellow Book estimates a global dengue burden of 390 million infections and 96 million symptomatic cases per year. These are annual global estimates, not a count of diagnosed U.S. travelers.
CDC defines frequent or continuous dengue risk as more than 10 dengue cases in at least three of the previous 10 years. Sporadic or uncertain dengue risk means at least one locally acquired dengue case during the last 10 years. These definitions describe how CDC classifies destination risk over a lookback period.
CDC says most dengue cases in the 49 continental U.S. states occur in travelers, and separately says most dengue cases reported in the continental United States occur in travelers infected elsewhere. CDC’s global dengue travel notices cover countries reporting higher-than-usual case numbers or higher-than-expected numbers of cases among U.S. travelers. Destination assessments can therefore change with local transmission and traveler surveillance.
Chikungunya prevention has a separate vaccine statistic. CDC says VIMKUNYA is approved for people 12 years and older and recommends chikungunya vaccination for adolescents and adults traveling to outbreak areas. CDC also considers the vaccine for people traveling or moving to elevated-risk areas for U.S. travelers when they expect to stay six months or more. These recommendations depend on destination and duration rather than applying to every trip.
Vaccination timing and protection
Vaccine schedules are among the most practical CDC travel health statistics because they turn destination risk into planning dates. Yellow fever vaccine is recommended for people aged 9 months or older who are traveling to or living in risk areas in Africa and South America. CDC says one dose is typically safe and provides lifelong protection. For travelers to ongoing outbreaks, CDC says a booster may be considered when 10 years or more have passed since the last vaccination.
Cholera vaccine timing and duration vary by product. Vaxchora is the only cholera vaccine approved for use in the United States, and the FDA approved it for travelers ages 2 through 64 years. It is a single oral dose that should be given at least 10 days before travel. The manufacturer reports a 90% reduction in moderate and severe diarrhea 10 days after vaccination and an 80% reduction at three months in adults ages 18 to 45 years. CDC says Vaxchora protection lasts at least three to six months.
| Cholera vaccine | Schedule or timing | Protection information |
|---|---|---|
| Vaxchora | One oral dose, at least 10 days before travel | At least 3–6 months, according to CDC |
| Dukoral | 2 doses, 1–6 weeks apart | Effective for 2 years, according to CDC |
| Dukoral for ages 2–5 | 3 doses, 1–6 weeks apart | Product schedule for this age group |
| Euvichol-Plus | 2 doses at least 2 weeks apart | At least 3 years after 2 doses; about 1 year after 1 dose |
Dukoral is given as two doses separated by one to six weeks. Children ages 2 to 5 years need three Dukoral doses given one to six weeks apart. CDC says Dukoral is effective for two years. Euvichol-Plus is approved for ages 1 year and older and is given as two doses at least two weeks apart. CDC says two doses of Euvichol provide protection for at least three years, while one dose provides short-term protection for about one year. Product availability and eligibility should be checked before relying on a schedule.
Measles vaccination also has a clear timing requirement. CDC recommends MMR vaccination at least two weeks before international travel. Two doses provide 97% protection against measles, while one dose provides 93% protection. Babies 6 through 11 months old should receive one early MMR dose before travel. People 12 months and older, including adults, should receive two total MMR doses before travel; when the series begins after 12 months, CDC says the doses are given 28 days apart for children, teens, and adults without immunity.
Rabies, polio, and hepatitis B schedules
Rabies preexposure prophylaxis, or PrEP, is a two-dose vaccination schedule given on days 0 and 7. CDC says this schedule protects people for up to three years. For selected travelers, the booster window can be between three weeks and three years after the first vaccine in the two-dose series. CDC says travelers going to areas where rabies is common and medical care is limited may consider PrEP.
Postexposure prophylaxis, or PEP, follows a different schedule. CDC says a standard rabies PEP series includes four vaccine doses on days 0, 3, 7, and 14 after the first medical visit. For immunosuppressed or immunocompromised people, CDC recommends a five-dose regimen that adds a day 28 dose. PrEP and PEP are therefore not interchangeable schedules.
Polio planning depends on prior vaccination and exposure risk. The routine childhood schedule uses four IPV doses at ages 2 months, 4 months, 6 to 18 months, and 4 to 6 years. Adults who are incompletely vaccinated should receive the remaining one or two IPV doses at least four weeks apart before departure. Fully vaccinated adults with increased exposure risk may receive one one-time IPV booster. A country with increased poliovirus risk may require proof of vaccination on the yellow ICVP when departing.
For non-immune travelers, CDC recommends a three-dose hepatitis B travel vaccine series at 0, 1, and 6 months. CDC says hepatitis B travel vaccination is especially relevant for countries where hepatitis B prevalence is 2% or higher.
The CDC Think Travel Vaccine Guide also recommends a two-dose Japanese encephalitis vaccine series for travelers. The initial series should be completed at least one week before travel, and a booster may be given at least one year after the primary series when ongoing exposure or re-exposure is expected. CDC recommends cholera vaccination for adults traveling to areas of active cholera transmission, with vaccination at least 10 days before travel. Meningococcal vaccination is recommended for travelers to the meningitis belt of sub-Saharan Africa, particularly during the dry season from December through June.
CDC’s FY 2027 budget lists 75 malaria publications planned for FY 2026 and 75 planned for FY 2027 as output targets. Those are planned publication targets, not counts of malaria infections, travelers, or completed clinical interventions.