History of yellow fever as a result of the numerous deaths, of the French company licensed to build the canal resulted in a massive financial crisis in France. History of yellow fever The evolutionary origins of yellow fever most likely lie in Africa. Phylogenetic analyses indicate that the virus originated from East or Central Africa, with transmission between primates and humans, and spread from there to West Africa. The virus as well as the vector "Aedes aegypti", a mosquito species, were probably brought to the western hemisphere and the Americas by slave trade ships from Africa after the first European exploration in 1492. The
Yellow fever vaccine and Brazil in 2017 have further increased demand, while straining global vaccine supply. Therefore, to vaccinate susceptible populations in preventive mass immunization campaigns during outbreaks, fractional dosing of the vaccine is being considered as a dose-sparing strategy to maximize limited vaccine supplies. Fractional dose vaccination refers to administration of a reduced volume of vaccine dose, which has been reconstituted as per manufacturer recommendations. The first practical use of fractional doses of the yellow fever vaccine was in response to the 2016 outbreak in the Democratic Republic of Congo. Yellow fever vaccine Yellow fever vaccine is a vaccine that protects against