@Doiea yes yellow fever does a vaccine. In Kenya you can actually get the yellow fever vaccine at the age of 9months if you live in certain areas of high risk of getting yellow fever. For instance if you leave in Baringo, Keiyo, Koibatek and Marakwet. Yellow fever vaccine is also given as a travellers vaccine. So if you have to travel to a country where you are at risk of getting yellow fever, you can need to get the yellow fever vaccine. So if you are traveling to Kenya from another country they will ask you at the airport on arrival if you have a yellow fever certificate (this shows that you have had the yellow fever vaccine). This is also done in other African countries such as South Africa, Cameroon just to mention a few.