Yellow fever, a disease spread by mosquitoes, has an extensive history spanning back to the 1600’s. Today, due mainly to vaccination, it has a much lesser impact on the developed (and developing) world, but this has not always been the case. Once considered the most dangerous infectious disease, yellow fever has been eradicated from most parts of the world, thanks to the yellow fever vaccine. In honor of National Immunization Awareness month, read on for a brief history of the disease and how vaccine development has helped eradicate yellow fever in many nations.