Yellow Fever is most commonly transmitted via the bite of an infected mosquito, and vaccination is recommended for travel to sub-Saharan Africa and tropical South America.
Risk for acquiring yellow fever is dependent on your travel destination and season of travel; for example, according to the CDC, Yellow Fever has an elevated risk of transmission in West Africa during the end of rainy season, usually July to October. The risk for Yellow Fever infection in South America, on the other hand, tends to increase between January and March. (Learn more about the CDC’s recommendations for vaccination by country and season.)
Many countries require proof of vaccination for those eligible to receive the vaccine. The vaccination is administered as a single injection, and the World Health Organization requires revaccination at 10-year intervals.
Please note that Yellow Fever vaccinations are only available in California, New Mexico, Oregon and Washington.