We are visiting the falls for 2 days mid December from Rio. Lots of mixed reports about the danger of either contracting yellow fever or dengue fever. We're not keen to have this injection due to potential side effects before we leave Australia in two weeks. I can't find recent studies on statistics of people actually getting this disease. Can anyone shed some light onto a) whether we should definitely vaccinate and b). Any recent cases in 2013. Appreciate any relevant information.