Yellow Fever: Global Cases, Impact & Prevention - WHO Data

The World Health Organization estimates 200,000 cases and 30,000 deaths annually from yellow fever, a mosquito-borne viral hemorrhagic disease. Most cases occur in sub-Saharan Africa and tropical South America.

Transmission

• Sylvatic (jungle) – monkeys ↔ forest mosquitoes (Haemagogus, Sabethes).
• Urban – human ↔ Aedes aegypti mosquitoes.

Prevention

• Vaccination – single dose of live attenuated 17D vaccine provides lifelong immunity for most; required for entry to endemic countries (International Certificate of Vaccination).
• Vector control – eliminate breeding sites, insecticides, screened housing.
• Personal protection – repellents, long sleeves, bed nets.

Clinical

Most infections asymptomatic or mild (fever, headache, myalgia). 15% progress to toxic phase: jaundice, hemorrhage, renal failure, shock; case-fatality 20–50%. No specific antiviral; supportive care only.

Yellow fever is a prime example of a vaccine-preventable disease with ongoing outbreaks in under-vaccinated populations.