Classification	Description	Risk of Infection	Vaccination Recommendation
Endemic	• Areas persistent of enzootic yellow fever virus transmission over long periods of time • Yellow fever vectors and non-human primate hosts present • Yellow fever cases reported: human and non-human primate • Yellow fever cases in humans before vaccine coverage • Sero-surveys show evidence of high infection • Stable transmission	High	Recommended
Transitional	• Areas bordering endemic zone with periodic evidence of transmission during yellow fever epizootic or epidemic expansion • Yellow fever vectors and non-human primate hosts present • Human cases may be reported at long intervals • Sero-surveys show past evidence of infection	Moderate to high	Recommended
Low potential for exposure	• Areas bordering yellow fever endemic or transitional areas • Yellow fever vectors and non-human primates hosts present • No human or non-human primate cases reported • Sero-surveys may demonstrate past evidence of infection, usually at low levels	Low	Generally not recommended*
No risk	• Areas where there is no risk of yellow fever transmission, as determined by absence of past or present evidence of yellow fever virus circulation in the area or environmental conditions are not conducive to yellow fever transmission	No	Not recommended

* Vaccination might be considered for a small subset of travellers whose itineraries would place them at an increased risk for exposure to yellow fever virus (e.g., prolonged travel, with heavy exposure to mosquitoes, inability to avoid mosquito bites)