Yellow fever virus is a mosquito-borne flavivirus that causes infections in human beings, with symptoms ranging from mild non-specific illness to severe disease with jaundice, hemorrhage, and death. YFV is endemic to tropical areas of Africa and South America, where, according to the World Health Organization (WHO), there are approximately 80,000–200,000 YFV cases worldwide with approximately 30,000 deaths annually. The case fatality rate (CFR) for yellow fever (YF) ranges from 20% to 50%.