Travel Medicine and Vaccination

Updated: Dec 16, 2019
  • Author: Bret A Nicks, MD, MHA; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
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In 2018, more than 1.4 billion travelers worldwide crossed international boundaries, compared to just 25 million in 1950. In 2019, it is predicted that more than 72 million Americans will travel outside the United States. [1, 2] Regardless of whether this travel is associated with tourism, humanitarian efforts, or globalization of industry, studies suggest only a small number of travelers seek appropriate pre-travel health advice. In addition, the composition of those traveling continues to become more diverse and medically complex, creating a vastly different perspective on travel-associated medical concerns, preparations, required medical knowledge, and post-travel care precautions. [3]

The image below depicts the ebola virus.

Ebola virus. Electron micrograph courtesy of the C Ebola virus. Electron micrograph courtesy of the Centers for Disease Control and Prevention.

See Ebola: Care, Recommendations, and Protecting Practitioners, a Critical Images slideshow, to review treatment, recommendations, and safeguards for healthcare personnel.

Also, see the 13 Travel Diseases You Need To Know  slideshow to help identify and manage infectious travel diseases.

With the decreasing global boundaries and increasing activities, travel medicine has become a rapidly evolving field of medicine. Classically, travel medicine focused on individuals traveling to developing countries with prevention and treatment of malaria, traveler's diarrhea, and general vaccinations as its primary goal. Travel medicine has subsequently become a dynamic multidisciplinary specialty that encompasses aspects of infectious disease, public health, tropical medicine, wilderness medicine, and immunization. Although these aspects are broad in reach, they are tightly integrated within the realm of travel medicine and require appropriate understanding prior to venturing out, as well as increased awareness of patients presenting with illness after recent travel.

Therefore, whether you are a humanitarian aid worker in Tanzania, a volunteer working in the previous Ebola-stricken areas of West and Central Africa, an educator in Samoa during the recent measles outbreak, a tourist, or a businessperson for a multinational corporation, understanding the dynamics of travel and the interplay of healthcare will minimize the adverse effect of travel-related illnesses and concerns while maximizing enjoyment and success for the trip.


Travel Medicine: The Big Picture

Travel medicine remains dynamic and increasingly broad in its medical knowledge requirements, as it focuses on the prevention, surveillance, and management of health issues related to global travel. Areas of expertise include vaccinations, epidemiology, region-specific travel medicine, pre-travel management, travel-related illnesses, and post-travel management. This increasing globalization of travel, well over 1 billion annually (with ~80% from developed-to-low/middle–income countries), facilitates increased health exposures in different environments and the potential spread of disease.

Although the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) provide the backbone of current medical considerations, several groups have taken a paramount role in developing a structured curriculum to better identify the realm and role of travel medicine as a subspecialty of care. Two such examples are the International Society of Travel Medicine (ISTM) and the American Society of Tropical Medicine and Hygiene (ASTMH). The formation of such groups has allowed for a more open dialogue about the required body of knowledge for the practice of travel medicine and thereby improved related resources to an ever-expanding diversity of travelers.

In addition, recent establishment of collaborative sentinel surveillance networks specifically to monitor disease trends among travelers offers new supplemental options for evaluating travel health issues. These networks can inform pre-travel and post-travel patient management by providing complementary surveillance information, facilitating communication and collaboration between participating network sites, and enabling new analytical options for travel-related research. TropNet and GeoSentinel represent examples of two major networks currently available. Data obtained from studying health problems among travelers may provide significant benefits for local populations in resource-limited countries. These should be considered as complementary tools and not relied on as an exclusive basis for evaluating health risks among travelers. [3]


Pre-travel Medical Preparation

Annually, Americans make more than 400 million trips to other countries. An increasing number of these trips are to low/middle–income countries. According to the CDC, 30-60% of these travelers, estimated at greater than 15 million people, become ill as a result of their travel. [4, 5]

With a heightened interest in adventure travel, international destinations, and ecotourism, more patients return from vacations with presentations of possible exotic disease that are beyond the scope of a primary care or emergency physician's daily practice. However, much of the illnesses encountered could be eliminated with adequate pre-travel education and preparation. In the circumstance when prophylactic treatment and lifestyle modification fail, physicians need to know what to look for and where to find information on exotic diseases beyond the scope of daily practice. Further information can be quickly and easily accessed through the CDC Yellow Book, an online resource providing country-specific information related to endemic diseases.

Pre-travel preparation

Whether the participant is on an extended excursion in Mongolia, serving at a medical mission in Belize, or is an adventure-seeking traveler, preparation is paramount to a successful venture. This preparation should begin during the planning stages of travel, preferably months in advance of departure to allow for any travel clinic and immunization needs. Travelers should become informed about the potential hazards of the countries they are traveling to and learn how to minimize any risk to their health. Forward planning, appropriate preventive measures, and careful precautions can substantially reduce the risks of adverse health consequences. Although the medical profession and the travel industry can provide a great deal of help and advice, the traveler is responsible to ask for information, to understand the risks involved, and to take the necessary precautions for the journey. In addition, consideration should be given to any underlying medical or comorbid condition of each traveler—as medications and emergency planning should be established prior to leaving.

Travelers should ascertain the associated travel health information, including general health information such as vaccine requirements, prophylactic medications, disease outbreaks, political environment, and medical resources. While much of this information can be found online, this should not exclude consideration for a pre-travel medical consultation and evaluation.

Although often overlooked, dental, and for women, obstetric/gynecologic (OB/GYN) checkups are advisable before travel to developing countries - especially for prolonged travel to remote areas. This is particularly important for people with chronic or recurrent dental, OB/GYN, or other health-related problems.

Approach to medical preparation for travel

Prior to departure for any extended or overseas travel, the following information should be obtained:

  • Geographic itinerary
  • Duration and month(s) of travel
  • Urban travel versus rural travel
  • Anticipated living conditions and resources
  • Purpose of travel
  • Medical care resources available during travel and health-related contingency planning, including evacuation insurance
  • Knowledge of any known disease risk or precautions advised (CDC is the best resource)
  • Understanding that re-entry into the United States or countries with connecting flights may be refused to travelers who have been exposed to some diseases or during specific illness outbreaks (ie, Ebola) [6]

Personal health information should be obtained and carried, including the following:

  • Personal health status (eg, age, weight, pregnant)
  • Medications and allergies
  • Past medical history
  • Medical or physical limitations

Basic health travel kit

A medical kit is an essential item that should be carried by all travelers to developing countries or where local availability of such resources remains in doubt. The kit should include standard first-aid items, simple medications for common ailments, and any items specific for that traveler. In addition, consider having a list of medications along with a medical attestation signed by a physician authenticating the need of those medications for personal use.

Some countries do not allow certain medications, commonly prescription pain medications, into the country without a physician letter and without medication being in the original pharmacy bottle. Standard toiletry items sufficient for the entire travel period are recommended. This would include tampons for women, which are not available in most countries). Procuring even the most basic items can be a challenge because of language barriers. [7, 8]

First-aid items to consider often include the following:

  • Antiseptic wound cleanser
  • Antihistamines
  • Wound coverings: Adhesive bandages, medical tape, sterile gauze
  • Eye drops
  • Nasal decongestant
  • Physicians may wish to carry a small suture kit
  • Hand antiseptic
  • Insect repellent/insect bite treatment
  • Some countries advise carrying sterile intravenous needle supplies
  • Oral rehydration powder
  • Scissors, safety pins/closure devices
  • Simple analgesics (eg, ibuprofen, acetaminophen)
  • Thermometer (oral/rectal)

Additional considerations include the following:

  • Antidiarrheal medication
  • Antinausea medication (if any water travel or winding roads anticipated)
  • Antifungal medication
  • Malaria prophylaxis (based on travel-clinic and/or CDC recommendations depending on destination)
  • Personal medications (current medical conditions)
  • Sleeping medications/sedatives
  • Water purifier/disinfectant

Resource utilization

Improvisation (ie, creative use of unusual supplies for diagnosing, treating, splinting, transporting) is an invaluable skill taught in Wilderness Medical Society (WMS) and other similar courses. Efficient selection and knowledge of medications lightens the medical kit. For example, rather than carrying multiple antibiotics of choice for several possible infections, consider carrying a medication, such as ciprofloxacin, which despite some growing resistancy issues, treats travelers' diarrhea (TD) as well as respiratory, wound, bladder, and other infections. Another example is diphenhydramine, which is excellent as an injectable local anesthetic as well as treatment for nausea, allergic reactions, and insomnia.

Unique circumstances

Physicians planning to serve as an expedition physician are advised to take a course provided by the WMS or a similar course by other providers. Detailed logistical planning, skills, equipment, medications, and resources for varied groups and destinations are beyond the scope of this article. Such information is readily available in both courses and textbooks from the WMS and the International Society of Travel Medicine (ISTM).

Almost any expedition has a unique set of possible emergencies, varying by destination and by the types of participants. Possible injuries and risks range from unusual envenomations and exotic flora and fauna to bear or shark attacks to snakebite or frostbite. Below is a list of possible scenarios that foster unique preparatory considerations:

  • An extended expedition in the Rocky Mountains with a group of Cub Scouts

  • An acutely ill patient with end-stage renal disease while aboard a 7-day luxury cruise ship sailing

  • Team physician on an Everest expedition

  • Marine biology study of the Great Barrier Reef

  • A bird-watching group of elderly people in the Amazon

  • A photo safari in Africa or fishing trip in Alaska

Requisite emergency skills may vary based on location, weather, activities, and availability of medical care resources. A physician may need knowledge of unusual diseases and injuries specific to certain activities or locations. These could include extrication and rescue skills in various environmental situations and improvisational skills and treatment of many medical emergencies. Many of these skills can be easily identified with adequate travel preparation and an understanding of the environment in which one will be traveling. However, regardless of the level of preparation, unplanned emergencies often occur, and one's level of preparation may dictate the success with which care is provided. [9, 10]


Vaccination and Immunization

In anticipation of upcoming travel, it is essential that one is well educated regarding the regions that will be visited and how one’s current level of health may be impacted. Vaccinations are a vital part of any preparatory process. Once the regions of anticipated travel are identified, scheduling a visit to one’s doctor or a travel medicine provider is essential—ideally 4-6 weeks before the trip because most vaccinations require a period of days or weeks to become effective. Reviewing current recommendations for the region of travel is recommended prior to the scheduled medical appointment. [11, 12] In addition, if uncertain regarding previous immunizations, variable tests are available to identify appropriate titer levels and whether updated boosters are indicated. [13]

When discussing vaccinations, considering which are essential based on the region of travel and planned activities and what may be recommended is prudent. In the Travelers' Health section, the CDC clearly delineates what one needs to know about vaccinations for a desired travel destination. Further, it helps separate vaccines into 3 categories: required, recommended, and routine.

Routine vaccinations

Routine vaccinations are the immunizations that are routinely provided as a part of one’s normal health maintenance (eg, tetanus immunization). These vaccines are necessary for protection from diseases that remain common in many parts of the world, although infrequently in the United States. If you are uncertain if you are up-to-date on routine immunizations, check with your medical provider.

Recommended vaccinations

Recommended vaccinations are predicated on a number of factors including one’s travel destinations, planned activities, season, previous immunizations, urban/rural location, one’s age, and current health status. In general, these vaccinations are recommended to protect travelers from illnesses present in other parts of the world and to prevent the importation of infectious diseases across international borders. For example, polio vaccine is now recommended for certain countries in the Middle East.

Travelers to cholera-affected regions should receive a cholera vaccine. The cholera vaccine (Vaxchora) is the only one approved by the FDA for cholera prevention available in the United States. It is a live weakened vaccine administered as a single oral liquid dose of about 3 fluid ounces at least 10 days before travel to a cholera-affected region. The only other existing cholera-prevention vaccines require 2 doses, according to the Centers for Disease Control and Prevention (CDC). A single-dose vaccine is especially beneficial to a person who needs to travel to a cholera-affected region on short notice. [14]

Special considerations for aging, immune compromised, pregnant, immigrant, chronically ill, students, and disabled travelers are essential.

Required vaccinations

International Health Regulations requires yellow fever vaccination for travel to certain countries in sub-Saharan Africa and tropical South America. In addition, those traveling during the Hajj are also required by the government of Saudi Arabia to obtain the meningococcal vaccination. Belize, among other countries, does not allow cruise ship or airplane passengers to disembark without yellow fever vaccination because of destinations the traveler(s) may have visited during the trip, not necessarily because yellow fever is in the country. Travel itineraries often do not explain these details. The recommendations are subject to change as new diseases invade new areas, and existing diseases may change or develop medication resistance (eg, malaria).


Common Medical Considerations

Whether dealing with altitude sickness, malaria, cholera, or dengue fever, having a basic understanding of the common illnesses specific to the region of travel is essential. However, the list of potential considerations globally is enormous and far beyond the scope of this section. A great resource to identify more specific information can be found online through the Diseases Related to Travel section of Travelers' Health on the CDC Web site. However, one of the most commonly experienced illnesses related to travel is diarrhea.

Travelers' diarrhea

By far, the most common health risk for travelers, especially those visiting developing countries, is traveler's diarrhea (TD), which can range from mildly annoying to prolonged, painful, and debilitating. According to the US CDC, high-risk destinations include the developing countries of Latin America, Africa, the Middle East, and Asia. Persons at particular high-risk include young adults, immunosuppressed persons, persons with inflammatory bowel disease or diabetes, and persons taking H2 blockers or antacids. [5, 1]

Every year, the CDC reports that 30-70% of international travelers (an estimated 12-15 million people) develop diarrhea, usually within the first week of travel. Traveler’s diarrhea, however, may occur at any time while traveling, even after returning home. The primary cause is contaminated food or water, typically found in areas with poor sanitation. Travelers should be advised to eat only food that is hot or boiled and to drink only bottled beverages, making certain the seal has not been broken prior to it being placed in front of them. This and meticulous handwashing can prevent nearly all cases of traveler’s diarrhea.

Common symptoms of traveler’s diarrhea include the following:

  • Abrupt onset

  • Increased frequency, volume, and weight of stool

  • Altered stool consistency

  • Nausea and/or vomiting may be associated

  • Abdominal cramping, bloating, flatus

  • Fever

  • Malaise

Treatment of traveler’s diarrhea

Most cases are benign and resolve in 1-2 days without treatment. Traveler’s diarrhea is rarely life threatening. Infectious agents are the primary cause of traveler’s diarrhea. Bacterial enteropathogens cause approximately 80% of traveler’s diarrhea cases. The most common causative agent isolated in countries surveyed has been enterotoxigenic Escherichia coli (ETEC). The natural history of traveler’s diarrhea is that 90% of cases resolve within 1 week, and 98% resolve within 1 month.

Although nearly 90% effective, antibiotics are not recommended as prophylaxis. Routine antimicrobial prophylaxis increases the traveler's risk for adverse reactions and for infections with resistant organisms, specifically extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-PE). Antibiotics provide no protection against either viral pathogens or parasitic pathogens; therefore, they can give travelers a false sense of security. As a result, strict adherence to preventive measures is encouraged, and bismuth subsalicylate should be used as an adjunct if prophylaxis is needed and the traveler is able to take it.

Because traveler’s diarrhea is usually self-limiting, oral rehydration is often the only treatment recommended. Clear liquids are routinely recommended for adults. If a traveler develops 3 or more loose stools in an 8-hour period and has associated nausea, vomiting, abdominal cramps, fever, or blood in stools, they may benefit from antimicrobial therapy. If vomiting is not well controlled or diarrhea is very frequent, oral rehydration salts are recommended and necessary.

When and how to treat traveler’s diarrhea requires the traveler to be the diagnostician, practitioner, and patient, so pretravel education is essential. Antibiotics, which should be reserved for moderate to severe cases, may reduce the duration of diarrhea by 1-2 days. While fluoroquinolones have been the drug of choice, increasing microbial resistance to the fluoroquinolones, especially among Campylobacter isolates, may limit their usefulness in some destinations such as Thailand, where Campylobacter is prevalent. Increasing cases of fluoroquinolone resistance have been reported from other destinations. Alternatives in this situation include azithromycin, rifaximin, or rifamycin SV. [8, 15]


Legal Issues

Malpractice and Good Samaritan laws differ from state to state and in foreign countries. Whether contracted to provide care for an expedition or volunteering at a medical clinic in a developing country, legal protection can vary as much as one's moral obligation to treat. Before understanding the specific nuances and details of medical liability with regard to wilderness and travel medicine, an understanding of the general framework is essential. However, this is a complex topic beyond the scope of this article. It is highly recommended to review the malpractice environment where care will be delivered, confirm the medical coverage, and assess the medical liability associated with the planned undertaking.

In general, physicians are required by law to keep a medical record of any prescription or treatment rendered anywhere. This includes prescriptions for a family member or giving an adhesive bandage for a blister to a stranger. In the unfortunate circumstance of a poor treatment outcome, a patient's signed release often will not protect a physician from a good lawyer or from a poorly informed jury. In the situation of unplanned medical care, one legal argument used against the Good Samaritan defense has been that possession of any medical equipment showed that the physician had planned to practice medicine and therefore was not protected by the Good Samaritan law. Situations may arise in which physicians feel a moral obligation to help but have no legal protection. Decide ahead of time where to draw the line.

Physicians who are paid to provide care to a group have increased liability and must ascertain the level of malpractice coverage. Even then, the insurer may limit coverage to a specified group, leaving the physician unprotected if he or she should treat an outsider dragged to the tent because someone heard that the group had a doctor.


Medical Tourism

Travel for the purpose of seeking health care is not new. In traditional medical tourism, patients used to travel to developed economies (i.e. Europe and US) to receive high-end treatments, owing to lack of or delays with treatment options in a patient's respective country. However, in recent years, the scenario has shifted to medical care being provided in developing countries with improving infrastructure and a focus on the lucratic medical tourism industry. It is currently reported that the medical and dental tourism industry exceeds $400 billion and growing. The reported cost savings for the treatments in these settings are 30-70% of the total treatment cost. The currently used definition of "Medical Tourism" refers primarily to a phenomenon of travelers leaving family and friends to seek care abroad, often in less developed countries, along with the organizations that support or offer incentives for such travel.

Exact measures of numbers of travelers involved in medical tourism are difficult to obtain, but it is estimated that up to 20 million medical tourists (1.9 million US residents) receive care beyond their borders annually. Increasingly, many of these destination countries (ie, Thailand, Malaysia, India, Turkey, Mexico) have advanced-level medical care with medical centers that may also have Joint Commission International accreditation. Not uncommonly for US residents born outside the United States, visits to their respective country of origin are often inclusive of healthcare needs, such as dentistry, because of familiarity with care in the country of origin, the high cost of health care in the United States, and lack of appropriate insurance coverage. [16]

The specific risks of medical tourism depend on the procedure being performed, the area being visited, the resources available for the procedure at that location, and the associated issues related to travel and follow-up care. As medical tourism continues to increase, physicians should be either familiar with up-to-date sources of information (eg, Travelers' Health) or referral options, and inquire whether or what role travel plays in their patient's life and medical care. The Joint Commission International is a US-based health care facility certification organization that will attest to specific care standards and may provide insight into a patient's desired care site.


Cruise Ship Medicine

Travel by cruise ship often congregates large groups of people from different parts of the United States and the world. In such settings, diseases (influenza, measles, rubella, Norwalk virus, gastrointestinal illnesses) can spread from person-to-person contact. Additionally, if a ship comes to port and passengers disembark to sightsee, they may be at risk for other geographic specific diseases, although such risk is difficult to quantify.

Note that certain diseases can be transmitted before symptoms are apparent and that some people who become ill while on a cruise ship may have been infected prior to travel. Add to that the complexity often seen with an increasingly mobile aging population with multiple medical problems and one can see that staffing a medical facility on a cruise ship can present many unique challenges.

While historically different, today, most cruise ships require a ship physician to have some emergency medicine experience. Many ships have minimal medications and few, if any, have laboratory or radiographic capabilities. However, some have mini–critical care units complete with monitors, ventilators, defibrillators/pacers, and appropriate medications. In general, the lack of resources can exhaust a physician's diagnostic and medical skills on a regular basis. One critical patient or an outbreak of Norwalk virus can overwhelm the ship’s hospital staff and use up all available resources while at sea.

Common medical conditions include the following:

  • Sunburn

  • Alcohol intoxication

  • Seasickness

  • Upper and lower respiratory infections

  • Diarrhea and subsequent dehydration

  • Minor orthopedic injuries

  • Geographic specific illnesses

  • Exacerbation of common medical illnesses

  • Major orthopedic injuries, cardiac, diabetic crisis, and cerebrovascular accident (CVA) are not uncommon

Cruise ships have onboard medical staff who should be sought for any illness. In addition, any traveler who becomes ill while onboard should see his or her health care provider upon returning home. Persons who are ill should limit contact with the general population on board as much as possible to reduce further spread of disease. Ship authorities will report infectious diseases of public health significance to state or federal health officials.

People planning cruise ship travel, especially those older than 65 years, those with acute or chronic illnesses, or those who are pregnant or breastfeeding should consult with a health care provider prior to travel for advice and possible preventive medication. Other measures to prevent the spread of infectious diseases on cruise ships include obtaining appropriate immunizations prior to leaving and frequent handwashing throughout the trip. Consider using portable alcohol hand cleanser after touching handrails, elevator buttons, salt shakers, or any other surface that may have been touched by hundreds of people that day. This is also true for hotels.

On the up side, cruise ship medicine is not all work and no play. Travel and entertainment opportunities are endless. The volume of patients seen and the level of illness may vary. Conversely, cruise ship epidemics may require the physician and staff to remain quarantined at sea for weeks. For more information on serving as a cruise ship physician, contact the ACEP Cruise Ship and Maritime Medicine Section.



Travel medicine is a dynamic field because conditions worldwide are subject to rapid change and are highly variable as it relates to the medical resources at hand. Clinicians must maintain a current base of knowledge encompassing a wide variety of disciplines including epidemiology, infectious disease, public health, tropical medicine, immigrant and refugee health, and occupational medicine. As a unique and growing specialty, it has become necessary to establish standards of practice in the field. These standards have been established to identify the scope of competencies expected of travel medicine practitioners, guide their professional training and development, and ensure a uniform level of patient care. Whether related to traveling abroad for leisure, work, or study, having updated health information, medications, and vaccinations helps to ensure safe and healthy travel.

Currently, the CDC advises all physicians to ask patients about recent travel abroad with specific focus to areas where Ebola and ongoing measles outbreaks are occurring with specific focus on areas involved with the West African Ebola outbreak. As outbreak locations continue to change, it is important to inquire about recent travel history for anyone presenting with acute illness. In addition, realizing that many serious diseases initially present similarly to common viral illnesses places even more importance on that travel history and the providers’ due diligence. With global travel being common, keep in mind that modern travel vessels, whether airplane or high-speed train, may contain passengers from 50 countries or 50 states. Documenting recent travel for a patient with ”the flu” may, one month later, provide a clue for the CDC or the WHO.

The following are important points to consider prior to departure:

  • Consult a travel medicine professional before leaving home. They can provide vital information for staying healthy, updating vaccinations and providing prophylactic and precautionary medications.

  • US travelers going overseas should enroll in the Smart Traveler Enrollment Program (STEP) to receive ongoing travel updates their area(s) of travel

  • Assess physical and medical limitations related to the anticipated travel; develop a care plan and follow the precautions related to the planned travel comorbid conditions.

  • Colds are a common problem among tourists, especially when confined to crowded conditions (eg, buses, cruise ships). Practice exquisite handwashing and limiting personal contact with others to minimize contamination.

  • Sexually transmitted diseases are frequently associated with unsafe practices while traveling. Avoid unsafe sex to protect yourself and your partner.

  • Gastrointestinal disorders are very common ailments among travelers. Purified hydration and good hygiene are essential.

  • Be aware of those traveling with you and help them get the proper medical attention when necessary.

  • Check with your insurance carrier as to whether you have international coverage and evacuation insurance. If not, consider a short-term policy during travel.

  • Remember when traveling globally, respect the unique aspects of the culture and people. Remain considerate to best ensure your trip is a pleasant, enjoyable experience.


Useful Resources

Available resources

See the list below:

Preparation for nonmedical emergencies

See the list below:

Recommended texts

See the list below:

  • CDC Yellow Book 2020: Health Information for International Travel (The Yellow Book). Oxford University Press; 2020.

  • Rose SR, Keystone JS. International Travel Health Guide; 2019 Online Edition.

  • Auerbach PS. Wilderness Medicine: Management of Wilderness and Environmental Emergencies. 7th ed. Mosby; 2017.