Yellow fever and several species of mosquitoes. In cities, it is spread primarily by "Aedes aegypti", a type of mosquito found throughout the tropics and subtropics. The virus is an RNA virus of the genus "Flavivirus". The disease may be difficult to tell apart from other illnesses, especially in the early stages. To confirm a suspected case, blood sample testing with polymerase chain reaction is required. A safe and effective vaccine against yellow fever exists, and some countries require vaccinations for travelers. Other efforts to prevent infection include reducing the population of the transmitting mosquito. In areas where yellow fever is common
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