1. Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes. The "yellow" in the name refers to the jaundice that affects some patients.

2. Symptoms of yellow fever include fever, headache, jaundice, muscle pain, nausea, vomiting and fatigue.

3. A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days.

4. The virus is endemic in tropical areas of Africa and Central and South America.

5. Large epidemics of yellow fever occur when infected people introduce the virus into heavily populated areas with high mosquito density and where most people have little or no immunity, due to lack of vaccination. In these conditions, infected mosquitoes of the Aedes aegypti specie transmit the virus from person to person.

6. Yellow fever is prevented by an extremely effective vaccine, which is safe and affordable. A single dose of yellow fever vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease. A booster dose of the vaccine is not needed. The vaccine provides effective immunity within 10 days for 80-100% of people vaccinated, and within 30 days for more than 99% of people vaccinated.

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http://www.humblemedicals.com/2018/12/yellow-fever.html