More about yellow fever

This page provides information about yellow fever and related vaccines.

Yellow fever is an acute, viral disease transmitted between humans by infected mosquitoes. The disease affects people of all ages and occurs in tropical areas, mainly in sub-Saharan Africa and parts of the Americas.
Many infections are mild, but the disease can cause severe, life-threatening illness. Initial symptoms include high fever, general muscle pain, backache, shivers, headache, loss of appetite, nausea, and vomiting. As the disease progresses (in about 15 percent of people infected), it can lead to shock, bleeding (from mouth, nose, eyes, and/or stomach), and kidney and liver failure. Half of the patients in this toxic phase die within 10 to 14 days. Those who recover from yellow fever have lifelong immunity against re-infection.
There is no specific treatment for yellow fever. Patients should drink plenty of fluids to compensate for dehydration.
An estimated 200,000 yellow fever cases with 30,000 deaths occur each year, almost all in sub-Saharan Africa, where over 508 million people in 33 countries are at risk of infection.
Yellow fever cases occur sporadically and can lead to outbreaks around urban centers. These outbreaks are best controlled by early detection and mass immunization of the at-risk population.

The live, attenuated yellow fever vaccine has been in use since the 1930s. The vaccine is safe, highly effective, and has few side effects. Serious side effects resulting from vaccination are extremely rare.
Adults and children more than nine months old can be vaccinated against yellow fever. The vaccine is not recommended for children less than six months, pregnant women, people with egg allergies, and people with suppressed immune systems.
A single dose of vaccine confers immunity within one week in 95 percent of people vaccinated. Immunity lasts for ten years or more at which time a booster shot is recommended for people living in endemic areas.
A yellow fever vaccination strategy involves a single preventive campaign of the at-risk population, followed by incorporation of the vaccine into routine immunization for infants, which has been shown to eliminate epidemic transmission.
Vaccination is highly recommended for travelers to high-risk areas and is seen as the single most important measure for preventing yellow fever.

Page last updated: August 2008.