Following the upsurge of yellow fever cases in new areas, the US Center for Disease Control and Prevention has expanded the regions where where vaccination against yellow fever is recommended (see dark orange areas):
Vaccination against yellow fever is strongly recommended for all travelers to regions where yellow fever occurs, even if it is not a mandatory requirement for entry into the country. See country-specific recommendations at www.healthytravel.ch.
Please note that the detailed country maps for yellow fever vaccination in Bolivia, Colombia, and Peru have not yet been updated by the CDC. Once available, they will also be updated on the respective country pages at www.healthytravel.ch.