Yellow Fever

Yellow fever is a viral infection transmitted by mosquitoes, found in parts of Africa and South America. Most infections are mild, but a proportion progress to a severe form affecting the liver and other organs, which can be fatal. It is preventable through a highly effective vaccine.

• Many infections are mild or asymptomatic
• Initial phase: fever, headache, muscle pain, nausea, and vomiting
• A minority progress after a brief improvement to a more severe phase with jaundice (yellowing of the skin and eyes, giving the disease its name), abdominal pain, and bleeding
• Severe cases can involve liver and kidney failure and are life-threatening

• Caused by the yellow fever virus, transmitted through the bite of infected Aedes or related mosquitoes.
• Occurs in defined endemic regions of Africa and South America.
• Risk is highest for people living in or travelling to endemic areas without vaccination.

• Suspected clinically based on fever with jaundice or bleeding in someone from or travelling to an endemic area, particularly if unvaccinated.
• Blood testing can confirm the diagnosis where available and is important for surveillance given the outbreak potential of yellow fever.

There is no specific antiviral treatment; care is supportive, focused on the specific complications that arise.

Mild cases are managed with rest, fluids, and paracetamol for fever (avoiding aspirin and NSAIDs due to bleeding risk).

Severe yellow fever requires hospital-level supportive care, including careful fluid management and monitoring or treatment of liver, kidney, or bleeding complications, ideally in an intensive care setting where the most severe cases are managed.

All suspected cases should be reported to health authorities, as yellow fever is subject to international health surveillance and outbreak response.

• Get vaccinated against yellow fever if living in or travelling to an endemic area — a single dose provides long-lasting protection for most people.
• Use mosquito repellent and protective clothing, especially during the day.
• Eliminate standing water around homes to reduce mosquito breeding.
• Check yellow fever vaccination requirements before international travel, as some countries require proof of vaccination for entry.