We have been in South America on a cruise and to Peru and the Galapagos last year and didn't need any yellow fever vaccine unless we were going into the Jungle. We are booked on a February cruise Santiago to Buenos Aires and haven't heard any mention of Yellow Fever vaccine needed. I have a liver problem and can't take the vaccine so I can't go to Africa or India. Mia, where are you going in S.A.? Check with your doctor or check the CDC website. I think it is only for travel into the Jungle or Amazon River.