Yellow Fever


Yellow fever is a serious viral infection that’s spread by certain types of mosquito. It’s mainly found in sub-Saharan Africa, South America and parts of the Caribbean.
The condition can be prevented with a vaccination and is a very rare cause of illness in travelers. If you’re planning to visit places where yellow fever infection is found, you should seek travel health advice about the vaccination available.

How yellow fever is spread

The virus that causes yellow fever is passed to humans through the bites of infected mosquitoes. The mosquitoes that spread the infection are usually active and bite during daylight hours, from dusk until dawn, and are found in both urban and rural areas.
Yellow fever can’t be passed directly from person to person through close contact.

Yellow fever symptoms

The symptoms of yellow fever occur in two stages. The initial symptoms develop three to six days after infection, and can include:

  • a high temperature (fever)
  • a headache
  • nausea or vomiting
  • muscle pain, including backache
  • loss of appetite

This stage will usually pass after three to four days and most people will make a full recovery. However, around 15% of people go on to develop more serious problems, including jaundice (yellowing of the skin and whites of the eyes), kidney failure and bleeding from the mouth, nose, eyes or stomach (causing blood in your vomit and stools).
Up to half of those who experience these symptoms will die.

When to seek medical advice

You should see a doctor as soon as possible if you develop symptoms of yellow fever and are currently travelling in an area where the virus is found, or have recently returned from one of these areas. To help determine whether you have yellow fever, the doctor will want to know exactly where you have been travelling and what symptoms you have. A blood test will be needed to confirm the diagnosis.

Treating yellow fever

There is no specific treatment for yellow fever, but the symptoms can be treated while your body fights off the virus. Headache, high temperature and muscle pain can be treated using painkillers such as paracetamol or ibuprofen. You should also drink plenty of fluids to avoid dehydration. If your symptoms are particularly severe, you may be admitted to hospital so that your condition can be monitored and you can receive supportive care.

Yellow fever vaccination

The vaccination against yellow fever should be given at least 10 days before travelling to an area where the infection is found, to allow your body to develop protection against the virus that causes the infection. Some countries require a proof of vaccination certificate before they will let you enter the country. This will only become valid 10 days after you are vaccinated.The yellow fever vaccination is given as a single injection and it offers protection to over 95% of those who have it.The protection offered by the vaccine may be life-long, but vaccination certificates are currently only valid for 10 years, and a booster dose may sometimes be needed after this time if you are planning another visit to an area where yellow fever is found. Even if you have been vaccinated, it’s still a good idea to take steps to prevent mosquito bites while you’re travelling – for example, by using mosquito nets, wearing loose, long-sleeved clothing, and applying insect repellent containing 50% DEET to exposed skin.