International travelers are at increased risk of exposure to infectious diseases. A key part of preparation for any trip includes seeking advice about what vaccines and other prophylactic measures may be necessary prior to departure. One can seek travel advice from his or her primary care physician or a specialized travel clinic. A pre travel consultation also allows for updating of routine immunizations (i.e. tetanus).
The vaccinations needs vary based on the traveler's prior immunizations, health conditions and the likely exposures at the travel destination. The risk depends on countries and regions visited and the nature of potential exposures. Needs are not the same for all travelers. Short term tourism may have different needs from those with plans for long term travel.
There are differences between countries with respect to vaccine guidelines and availability. The World Health Organization (WHO) has published an international perspective on vaccines. In the United States, available travel vaccines include yellow fever, meningococcal, typhoid, hepatitis A & B, polio, rabies, cholera and Japanese encephalitis. Here we will review some of the more common travel vaccines based on CDC guidelines and recommendations.
Hepatitis A vaccine
This viral infection is transmitted via the fecal-oral route and in very rare cases can lead to full on liver failure. Risk of transmission is decreasing due to improved sanitation in many parts of the world.
Who should get the vaccine?
All travelers that are going to countries with high risk of exposure or known endemic hepatitis A. A complete list of these countries can be found on the CDC website. However, given the potential risk of food borne hepatitis A even in countries with low endemicity, some experts advise those considering travel outside the United States to consider this vaccine regardless of the destination.
Who should not get the vaccine?
Those with a hypersensitivity to the vaccine or any of the components of the formulation should not get this vaccine. This vaccine is considered to be safe for use in pregnancy and in immunocompromised travelers.
The vaccine
A single injection administered prior to departure provides adequate protection for healthy individuals. A second dose may be needed in 6 to 12 months after the initial vaccine for longer term protection. The available combination vaccines include Twinrix (includes Hepatitis B) and Vivaxim (includes typhoid). Neither of these combination vaccines are available in the United States. For unvaccinated travelers who require post exposure prophylaxis during or after travel, immune globulin may be administered along with the hepatitis A vaccine.
Hepatitis B vaccine
This viral infection is transmitted by exposure to bodily fluids and can lead to liver failure or liver cancer. There are around 350 million hepatitis B carriers in the world. Of those it is estimated that roughly one million die annually from infection related liver disease.
Who should get the vaccine?
Vaccination is recommended for travelers to countries with intermediate to high endemicity of hepatitis B. Major risk groups include health care workers, adventure travelers, Peace Corps volunteers, missionaries, military personnel, and medical tourists.
Vaccination should also be considered in any traveler with potential contact with blood or bodily fluids, sexual contact or potential need for medical or dental procedures while traveling.
This vaccine should be considered for all non immune travelers since it is difficult to assess risk during pre travel consultation.
Who should not get the vaccine?
Hypersensitivity to this vaccine or any component of the formulation is a contraindication. Hepatitis B vaccine can be given to immunosuppressed patients.
The vaccine
This vaccine is given as a intramuscular dose. An initial dose is followed by repeat vaccination at one and six months after the first dose.
Meningococcal vaccine
This is a devastating bacterial infection with high mortality. There have been epidemics of this disease in what is known as the “meningitis belt” of Africa.
Who should get the vaccine?
Meningococcal ACWY vaccine is recommended for travel to the meningitis belt in Africa, especially from December to June (the dry season). Those with immune disorders such as terminal complement component deficiency or functional asplenia or surgical removal of the spleen should get this vaccine. Travelers to Saudi Arabia during Hajj are required to have proof of vaccination prior to entering.
Who should not get the vaccine?
Hypersensitivity to other meningococcal containing vaccines in a contraindication. This vaccine is safe for those who are immunocompromised and a history of Guillain-Barre syndrome is not a contraindication.
The vaccine
This vaccine requires a booster after initial vaccination. Protection significantly wanes after three years.
Typhoid vaccine
Typhoid is a bacterial disease with fecal-oral transmission and is characterized by fever and abdominal pain. Salmonella enterica Typhi infection is prevalent in Asia, Africa and Latin America. Some strains have become resistant to multiple antibiotics. This is available as Ty21a which is a live vaccine taken orally along with Vi polysaccharide, Vi-TT and TCV.
It is important to note that none of these are completely effective against typhoid and none have shown to be effective against paratyphoid fever.
Who should get the vaccine?
Typhoid vaccine is recommended for travelers to areas with a risk of exposure to typhoid. This risk increases with the duration of stay, although there are cases of illness with travel of less than one week to areas where the disease is endemic. Those at highest risk are travelers visiting friends or relatives.
Who should not get the vaccine?
The oral typhoid vaccine is a live attenuated vaccine and should not be taken by those with any type of immunodeficiency, acute febrile or gastrointestinal illness.
The vaccine
This is a single intramuscular injection and a booster dose is recommended after two years in the United States. The oral typhoid vaccine is administered as a four dose course (days 1, 3, 5, and 7) and needs to be repeated five years after initial administration.
Rabies vaccine
Rabies is a viral illness that is transmitted by dogs, bats, and other animals. Once infected, the natural course is encephalopathy and death. Rabies is endemic in most countries in Asia, Africa, and Central/South America.
Who should get the vaccine?
Pre exposure vaccination is indicated for travelers visiting areas where rabies is endemic who anticipate contact with animals and limited access to immediate medical care. Children are at increased risk as they are more likely to play with animals and may not reliably report exposures not associated with significant injury. Such minor injuries are enough to contract the virus.
Who should not get the vaccine?
Hypersensitivity to the vaccine or any component of the formulation is a contraindication. The vaccine can be given to immunocompromised and pregnant individuals.
The vaccine
In the United States the pre exposure vaccine consists of a series of intramuscular injections on day 0, 7, and 21 or 28.
Japanese encephalitis vaccine
This viral illness causes inflammation of the brain is endemic throughout most of Asia and some parts of the western Pacific. Highest risk is in rural agricultural areas associated with rice production and flooding irrigation. The vaccine available in the United States is an inactivated mouse brain derived vaccine.
Who should get the vaccine?
This vaccine may be needed for travelers to endemic areas.
Who should not get the vaccine?
Hypersensitivity to the vaccine or any component of the formulation is a contraindication.
The vaccine
This is a two part intramuscular vaccine administered either 7 days or 28 days apart. The vaccinations should be completed at least one week prior to travel.
Cholera Vaccine
Cholera is a diarrheal disease caused by infection with the bacterium Vibrio cholerae. It is characterized by severe watery diarrhea which can quickly lead to dehydration. Epidemics occur around the world, most recently in Yemen, but infection among travelers is uncommon. In the United States, the available vaccine approved by the FDA in June 2016 is a live attenuated oral vaccine.
Who should get the vaccine?
The live attenuated oral cholera vaccine is recommended for prevention of cholera caused by serogroup O1 in adults 18 to 64 years of age who are traveling to affected areas (i.e. Yemen) who are at immediate risk of epidemic cholera.
This vaccine has not been shown to protect against disease caused by serogroup O139 or other serogroups. The groups that most likely need vaccination include aid, refugee, and health care workers in endemic and epidemic areas.
Who should not get the vaccine?
This vaccine may be shed in the stool of recipients for up to one week with the potential for transmission to non vaccinated household contacts. The safety and effectiveness of the vaccine has not been established in immunocompromised individuals.
The vaccine
A single oral dose taken at least 10 days prior to travel is sufficient.
Yellow fever is a mosquito borne viral infection that is endemic in Africa and South America. There is no cure for the disease and once contracted, supportive care is the treatment.
Although rare, deaths due to yellow fever have been reported. International Health Regulations allow some endemic countries to require proof of this vaccine for entrance.
Airport transit stops in an endemic country usually does not require proof of vaccination. Keep in mind that some countries that have endemic yellow fever do not have a legal requirement for vaccination and if you plan to travel to those countries vaccination is recommended for your own protection.
The yellow fever vaccine is a live virus that is grown in chick embryos. This vaccine is effective approximately two weeks after it is administered. A single dose of the vaccine is considered to be effective for lifelong protection according to the World Health Organization (WHO).
However, some require revaccination if more that 10 years has passed since last vaccination. The Centers for Disease Control and Prevention (CDC) recommends revaccination for long stay travelers, all travelers going to high risk areas such as West Africa, any travel to area with current outbreak as well some other high risk travelers.
Who should get the vaccine?
Travelers ages 9 months and older who are traveling to or living in high risk areas.
Who should not get the vaccine?
This is a live vaccine. It should not be given to travelers with immunodeficiencies, transplant recipients, patient on immunosuppressive medications or those with HIV who have a CD4 count less than 200/ml.
Others who should not get this vaccine include those younger than 6 months of age, allergy to the vaccine and thymic disorders. For those older than 60 or infants younger than 9 months the risk of contracting the disease needs to be weighed against the risk serious vaccine side effects.
Pregnancy complicates things and vaccine administration should be discussed with a medical doctor.
Potential complications of the Yellow fever vaccine
Hypersensitivity or anaphylactic reactions are exceedingly rare and tend to occur in those with egg allergies. This vaccine is associated with two serious adverse reactions. The first is a neurologic disease (YEL-AND) which is serious but rarely fatal and the other is vaccine associated viscerotropic disease (YEL-AVD) which mimics yellow fever illness. Fortunately both are rare.
The vaccine
This is a single subcutaneous injection. It should be administered either at the same time or at least 30 days apart from other live viral vaccines.
Conclusion
Travel vaccinations are a vital part of preparing for international travel. They not only protect your health but also contribute to the well-being of the communities you visit by preventing the spread of infectious diseases. To ensure a safe and enjoyable journey, consult with a doctor, stay informed, and plan your vaccinations well in advance. By taking these proactive steps, you can explore the world with confidence, knowing that you've taken important measures to safeguard your health.
This information is dynamic and is based on current recommendations from internationally recognized organizations such as the Centers for Disease Control and Prevention, Advisory Committee on Immunization Practices and the World Health Organization. This is meant to serve as an educational source and is not to be take as medical advice in any way. Please consult with your doctor prior to travel to assess your needs for travel vaccinations.
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Safe travels.
Please remember that medical information provided by us must be considered an educational service only. This blog should not be relied upon as medical judgement and does not replace your physician’s independent judgement. This is NOT medical advice. Please seek the advice of your physician.
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