What are current recommendations on travel vaccine administration?

Introduction
International travel can contribute to the spread of several health concerns, including COVID-19, the Ebola virus, the Zika virus, and bacterial infections resistant to antibiotics. 1 According to the United Nations, international travel is rapidly approaching pre-pandemic levels; at the end of 2023, international flight arrivals approached 88% of what they used to be.2 Individuals planning an international trip should consult a healthcare professional about possible health risks and how to best safeguard their health to reduce the chance of contracting an illness.3 Planning ahead, taking the right preventive steps, and exercising extreme caution can safeguard traveler’s health and reduce the likelihood of disease transmission.

Travel Vaccines Guidance
One way to take preventative health measures when traveling abroad is to be up-to-date on travel immunizations. The Centers for Disease Control and Prevention (CDC) outlines general principles of vaccination and immunoprophylaxis in their 2024 Yellow Book for travel health.1 They recommend travelers make a pretravel health consultation in order to discuss travel health risks and concerns. Key elements of a pretravel health consultation include: health status, the destination(s), the length and purpose of the trip, the mode of transportation, the standards of lodging and food hygiene, and planned activities.3 During this assessment, it is important that the traveler provides a personal record of any vaccinations they have received in order to determine what else they may need prior to travel.

In terms of vaccinations, there are 3 categories to consider: required, routine, and recommended vaccines.4 In the United States, routine vaccinations are advised for all individuals (depending on personal characteristics including age, risk factors, health issues etc). Required vaccines are in accordance with the laws of each individual country, and tourists are required to obtain the necessary vaccinations before entering that nation. Recommended vaccines are what the CDC advises travelers to get, even if they are not mandated by the country they are visiting; this may vary depending on a number of variables, including the location, the traveler’s health status, and the activities they have scheduled. The majority of common vaccines can typically be administered at different injection sites during the same visit without affecting antibody responses or raising the risk of adverse events.1 When administering recommended immunizations at the same time, it is especially beneficial for travelers who may soon be exposed to multiple infectious diseases. To note: if a live-virus vaccine (such as the measles-mumps-rubella [MMR], varicella, or live attenuated influenza vaccines) is given within 28 days of another live-virus vaccine, the immune system’s ability to respond to the first vaccination may be compromised. The CDC also provides a list of non-routine travel vaccinations that are now accessible in the United States, such as the rabies, inactivated typhoid, yellow fever, and Japanese encephalitis vaccines. A full list of routine and non-routine travel vaccination guidance can be found on the CDC Yellow Book website (https://wwwnc.cdc.gov/travel/page/yellowbook-home).

Travel health notices are also important to take note of prior to any domestic or international travel. The CDC issues travel health notices to advise travelers on precautions they can take to avoid infection or negative health impacts, as well as to advise them about global health risks.4 A travel health notice may be issued in the following situations: disease outbreak in a nation or region; occasional cases of a disease in an uncommon or new geographic location; both man-made and natural disasters that pose a serious threat to public health or infrastructure damage that would restrict access to healthcare services; and large-scale gatherings that may spark disease outbreaks.

One such travel health risk in the Americas is dengue which has been labeled as a Level 1 travel health notice by the CDC.5 This means that travelers should practice usual precautions when visiting many parts of Central and South America, the Caribbean, and Mexico. Dengue is spread via mosquito bites, and a few ways that travelers can protect themselves is by dressing in long sleeves and long pants when they go outside, sleeping in an air-conditioned room or a room with window screens or under a bed net treated with insecticide, and using an environmental protection agency (EPA)-registered insect repellent. Another preventative option is Dengvaxia (the first Dengue vaccine approved in the United States).6 It is a live vaccine which is approved for use of people (ages 9 to 16 years) who are living in dengue-endemic areas and who have laboratory evidence of previous dengue infection. It is administered as a 3-dose subcutaneous injection series given at 0, 6, and 12 months. It is important to note that Dengvaxia is not approved for travelers living in nonendemic dengue areas who are visiting a dengue-endemic area.

References

  1. Centers for Disease Control and Prevention (CDC). CDC Yellow Book 2024: Health information for international travel. New York; 2023; online edn, Oxford Academic. Published March 23, 2023. https://doi.org/10.1093/oso/9780197570944.001.0001. Accessed April 30, 2024.
  2. International tourism to reach pre-pandemic levels in 2024. www.unwto.org. Published January 19, 2024. Accessed April 30, 2024. https://www.unwto.org/news/international-tourism-to-reach-pre-pandemic-levels-in-2024
  3. International travel and health. World Health Organization. January 2019. Accessed April 30, 2024. https://www.who.int/publications/i/item/9789241580472.
  4. Travelers’ health. Centers for Disease Control and Prevention. Accessed April 30, 2024. https://wwwnc.cdc.gov/travel/.
  5. Dengue in the Americas. Centers for Disease Control and Prevention. May 16, 2024. Accessed June 4, 2024. https://wwwnc.cdc.gov/travel/notices/level1/dengue-americas.
  6. Dengue vaccine resources. Centers for Disease Control and Prevention. Accessed June 4, 2024. https://www.cdc.gov/dengue/hcp/vaccine/resources.html#cdc_listing_res2-clinical-resources

Prepared by:
Faria Munir, PharmD, MS, BCPS
Clinical Assistant Professor, Drug Information Specialist
University of Illinois at Chicago College of Pharmacy

May 2024

The information presented is current as of June 4, 2024. This information is intended as an educational piece and should not be used as the sole source for clinical decision-making.