The following pages present country-specific information on yellow fever (YF) vaccine requirements and recommendations, and malaria transmission information and prevention recommendations. Country-specific maps are included to aid in interpreting the information. The information in this chapter was accurate at the time of publication; however, it is subject to change at any time due to changes in disease transmission or, in the case of YF, changing entry requirements for travelers. Updated information reflecting changes since publication can be found in the online version of this book and on the Centers for Disease Control and Prevention (CDC) Travelers’ Health website. Recommendations for prevention of other travel-associated illnesses can also be found on the CDC Travelers’ Health website.
Entry requirements for proof of YF vaccination under the International Health Regulations (IHR) differ from CDC’s YF vaccination recommendations. Under the IHR, countries are permitted to establish YF vaccine entry requirements to prevent the importation and transmission of YF virus within their boundaries. Certain countries require proof of vaccination from travelers arriving from all countries (Table 5-25); some countries require proof of vaccination only for travelers above a certain age coming from countries with risk for YF virus transmission. The World Health Organization (WHO) defines areas with risk for YF virus transmission as countries or areas where YF virus activity has been reported currently or in the past, and where vectors and animal reservoirs exist.
Unless issued a medical waiver by a yellow fever vaccine provider, travelers must comply with entry requirements for proof of vaccination against YF.
WHO publishes a list of YF vaccine country entry requirements and recommendations for international travelers approximately annually. But because entry requirements are subject to change at any time, health care professionals and travelers should refer to the online version of this book and the CDC Travelers’ Health website for any updates before departure.
CDC’s YF vaccine recommendations are guidance intended to protect travelers from acquiring YF virus infections during international travel. These recommendations are based on a classification system for destination-specific risk for YF virus transmission: endemic, transitional, low potential for exposure, and no risk (Table 2-08). CDC recommends YF vaccination for travel to areas classified as having endemic or transitional risk (Maps 5-10 and 5-11). Because of changes in YF virus circulation, however, recommendations can change; therefore, before departure, travelers and clinicians should check CDC’s destination pages for up-to-date YF vaccine information.
In 2015, the US Advisory Committee on Immunization Practices published a recommendation that 1 dose of YF vaccine provides long-lasting protection and is adequate for most travelers. The recommendation also identifies specific groups of travelers who should receive additional doses, and others for whom additional doses should be considered (see Sec. 5, Part 2, Ch. 26, Yellow Fever). In July 2016, WHO officially amended the IHR to stipulate that a completed International Certificate of Vaccination or Prophylaxis is valid for the lifetime of the vaccinee, and YF vaccine booster doses are not necessary. Moreover, countries cannot require proof of revaccination (booster) against YF as a condition of entry, even if the traveler’s last vaccination was >10 years ago.
Ultimately, when deciding whether to vaccinate travelers, clinicians should take into account destination-specific risks for YF virus infection, and individual risk factors (e.g., age, immune status) for serious YF vaccine–associated adverse events, in the context of the entry requirements. See Sec. 5, Part 2, Ch. 26, Yellow Fever, for a full discussion of YF disease and vaccination guidance.
| YF VACCINE RECOMMENDATION CATEGORY | RATIONALE |
|---|---|
| Recommended | Vaccination recommended for all travelers ≥9 months old going to areas with endemic or transitional YF risk, as determined by persistent or periodic YF virus transmission |
| Generally not recommended | Vaccination generally not recommended for travel to areas where the potential for YF virus exposure is low, as determined by absence of reports of human YF and past evidence suggestive of only low levels of YF virus transmission |
1 This table is an abbreviated version of Table 1 from: Jentes ES, Poumerol G, Gershman MD, et al. The revised global yellow fever risk map and recommendations for vaccination, 2010: consensus of the Informal WHO Working Group on Geographic Risk for Yellow Fever. Lancet Infect Dis. 2011 Aug;11(8):622– 32. The categories of risk of YF virus transmission and corresponding categories of YF vaccine recommendations that appear here are taken unchanged from the referenced article.
The following recommendations to protect travelers from malaria were developed using the best available data from multiple sources. Countries are not required to submit malaria surveillance data to CDC. On an ongoing basis, CDC actively solicits data from multiple sources, including WHO (main and regional offices); national malaria control programs; international organizations; CDC overseas offices; US military; academic, research, and aid organizations; and the published scientific literature. The reliability and accuracy of those data are also assessed.
If the information is available, trends in malaria incidence and other data are considered in the context of malaria control activities within a given country or other mitigating factors (e.g., natural disasters, wars, the coronavirus disease 2019 pandemic) that can affect the ability to control malaria or accurately count and report it. Factors such as the volume of travel to that country and the number of acquired cases reported in the US surveillance system are also examined. In developing its recommendations, CDC considers areas within countries where malaria transmission occurs, substantial occurrences of antimalarial drug resistance, the proportions of species present, and the available malaria prophylaxis options.
Clinicians should use these recommendations in conjunction with an individual risk assessment and consider not only the destination but also the detailed itinerary, including specific cities, types of accommodations, season, and style of travel, as well as special health conditions (e.g., pregnancy). Several medications are available for malaria prophylaxis. When deciding which drug to use, consider the itinerary and length of trip, travelers’ previous adverse reactions to antimalarials, drug allergies, medical history, and drug costs. For a thorough discussion of malaria and guidance for prophylaxis, see Sec. 5, Part 3, Ch. 16, Malaria.