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🩺 Medically reviewed by theHealth Decoded Guide Editorial Team · Last reviewed: July 2026
🚨 Current Outbreak Notice (as of July 2026)
Yellow fever outbreaks are currently active in parts of South America (especially Colombia, where cases have a case fatality rate above 40%) and ongoing transmission continues in several high-risk countries in Africa. Almost all confirmed cases are in unvaccinated people.
If you're travelling to or from an at-risk area, check whether vaccination is recommended — one dose gives lifelong protection for most people. See WHO or TravelHealthPro/UKHSA for current guidance.
👉 This section will be updated as the situation develops.
🔍 Quick Summary
Yellow fever is a viral infection spread by infected mosquitoes in parts of Africa and South America.
Many people recover completely, but severe yellow fever can cause liver damage, bleeding and organ failure. Vaccination is the best way to prevent the disease.
1️⃣ Introduction
Yellow fever is caused by the yellow fever virus, which belongs to the flavivirus family.
• it is spread through the bite of infected mosquitoes
• it cannot spread through casual contact with an infected person
• vaccination provides strong and long-lasting protection
👉 Yellow fever remains an important public health concern in countries where the virus is present.
2️⃣ How it happens
A mosquito becomes infected after biting a person or animal carrying the virus.
• the infected mosquito bites another person
• the virus enters the bloodstream
• it can spread to the liver and other organs
👉 Most infections are mild, but some people develop severe disease a few days after initial recovery.
3️⃣ Types
Mild yellow fever
• fever and body aches
• recovery usually occurs within a few days
Severe yellow fever
• liver and kidney damage
• bleeding and organ failure may occur
👉 Only a small percentage of infected people develop severe disease, but it can be life-threatening.
4️⃣ Common causes
Mosquito exposure
• bites from infected mosquitoes
• living in or travelling to endemic areas
Lack of vaccination
• not receiving the yellow fever vaccine before travel
• low vaccination coverage in communities
👉 Vaccination is the most effective way to prevent yellow fever.
5️⃣ Symptoms
• sudden fever
• headache
• muscle pain, especially in the back
• chills
• nausea and vomiting
• loss of appetite
👉 Some people improve after a few days, while others develop severe symptoms later.
6️⃣ Associated symptoms or complications
• yellowing of the skin and eyes (jaundice)
• abdominal pain
• bleeding from the nose, mouth or stomach
• kidney failure
• confusion or seizures
👉 Jaundice after a recent fever is a warning sign that needs urgent medical attention.
7️⃣ 🩺 When it becomes dangerous 🚨
• yellow eyes or skin
• vomiting blood or passing black stools
• confusion or seizures
• severe abdominal pain
• difficulty breathing
👉 These may indicate:
• severe yellow fever with organ damage
• need for urgent medical assessment
8️⃣ Management / treatment
• hospital care for severe illness
• intravenous fluids and supportive treatment
• oxygen or intensive care if needed
• treating complications as they arise
👉 There is no specific antiviral treatment, but early supportive care improves survival.
9️⃣ Diagnosis
• medical history, including travel history
• physical examination
• blood tests to detect the virus or antibodies
• liver and kidney function tests
👉 Recent travel to an area where yellow fever occurs is an important clue.
🟢 Important Message
Yellow fever is largely preventable.
👉 If you are travelling to a country where yellow fever occurs, get vaccinated before your trip and protect yourself from mosquito bites.
FAQ
• Can yellow fever spread from one person to another?
No. It spreads through infected mosquitoes, not through casual contact.
• Is there a cure for yellow fever?
No. Treatment focuses on supporting the body while it fights the infection.
• Does one vaccine last for life?
For most people, a single dose provides long-lasting, often lifelong, protection.
• Can yellow fever be prevented?
Yes. Vaccination and mosquito bite prevention are the best forms of protection.
🧠 Why We Delay
Many people mistake the early symptoms of yellow fever for malaria, flu or another common viral illness. Others may not realise they need vaccination before travelling to areas where the disease occurs.
Delaying medical care can allow severe complications such as liver failure, bleeding and kidney injury to develop. Early assessment is especially important if fever is followed by yellowing of the eyes or unusual bleeding.
👉 Fever after travel to a yellow fever-risk area should never be ignored.
🔗 Related Health Topics
• Malaria
• Dengue Fever
• Viral Haemorrhagic Fever
• Mosquito Bite Prevention
• Travel Vaccinations
📚 Medical References
• World Health Organization (WHO). Yellow fever.
• Centers for Disease Control and Prevention (CDC). Yellow Fever.
• National Health Service (NHS). Yellow fever.
• Mayo Clinic. Yellow fever.
• UK Health Security Agency (UKHSA). Yellow fever guidance.
⚠️ Medical Disclaimer
This article is for educational purposes only and does not replace professional medical advice.
If you have concerning symptoms, risk factors or abnormal test results, consult a healthcare professional.