The yellow fever virus is found mainly in tropical and subtropical regions of Africa and South America. U.S. travelers very rarely are infected with yellow fever, says the Centers for Disease Control and Prevention. It's transmitted by infected mosquitos, and most people do not experience any symptoms or they are very mild. Those who do experience symptoms can have chills, fever, headache, back pain and body aches, nausea and vomiting, and weakness and fatigue.
The CDC says that about 15 percent of people develop a more severe form of the disease, which includes high fever, jaundice, bleeding, shock and failure of organs.
If you plan to visit one or more of the countries listed below, be sure you have been vaccinated for yellow fever before you leave home. Yellow fever vaccinations and boosters are good for 10 years, the CDC says.
Countries Requiring Proof of Yellow Fever Vaccination from U.S. Travelers
These countries are listed on the World Health Organization's International Travel and Health website as requiring proof of a vaccination for yellow fever for all travelers entering the country, including from the U.S., as of 2017. Other countries not on this list only require proof of yellow fever vaccination if you are coming from a country with a risk of yellow fever transmission or have been in an airport in any of those countries. Most countries not in the yellow fever zone do not require proof of yellow fever vaccination.
Check other countries' requirements on the WHO list.
- Central African Republic
- Cote d'Ivoire (Ivory Coast)
- Democratic Republic of the Congo
- French Guiana
- Sierra Leone