Yellow fever

Yellow fever is a serious viral infection that is 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 travellers.

Between 1999 and 2018, there was twelve cases of yellow fever reported among European travellers. None of these travellers were vaccinated, 5 of these cases occurred in 2018.

If you're planning to visit places where yellow fever infection is found, you should seek travel health advice before you travel. A map and list of countries where yellow fever is found is available on the NHS Fit for Travel website.

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, 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 you will be monitored and the symptoms can be treated. You will be admitted to hospital for assessment and 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 is lifelong for most people. Vaccination certificates are also valid for life.

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.

Read more about the yellow fever vaccination.

Information about you

If you have yellow fever, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the register.

If you are planning to travel to an area where you may be at risk of yellow fever, make sure you are vaccinated before making your trip.

About the yellow fever vaccine

The yellow fever vaccine is given as a single injection.

You should be vaccinated at least 10 days before you travel, as this will allow enough time for your body to develop protection against the yellow fever infection. Your proof of vaccination certificate (see below) will only become valid after this time.

The vaccination provides protection for 95-100% of those who have it. For most people this protection is lifelong,with some exceptions (see below).

Booster doses of yellow fever vaccine

Booster doses of the yellow fever vaccine used to be recommended every 10 years for everyone planning another visit to an area where the infection is found. However, booster doses are no longer required for most people.

From June 2016, vaccination certificates have been valid for the life of the person vaccinated, so a booster dose of yellow fever vaccine can't be required to gain entry into a country.

All certificates, even those issued before 2016, are now considered to be valid for life.

Booster doses are only recommended if you're travelling to an at-risk area and you were originally vaccinated when:

• you were pregnant
• you were less than two years old
• you had a weakened immune system (for example, due to an HIV infection or preparation for a bone marrow transplant)

Your local designated yellow fever vaccination centre (see below) should be able to advise you if you’re not sure whether you need to have a booster vaccination before travelling.

Where can I be vaccinated against yellow fever?

Yellow fever vaccinations can only be given at designated centres. For a centre to become a designated yellow fever vaccination centre, it must register with the appropriate authority. In the UK, this is either:

• Health Protection Scotland (HPS)
• the National Travel Health Network and Centre (NaTHNaC)

Find your nearest yellow fever vaccination centre.

The vaccination is not available for free on the NHS, so you will have to pay for it. On average, a single vaccination costs around £60.

Certificate of yellow fever vaccination

Under regulations set out by the WHO, anyone travelling to a country or area where there is a risk of picking up or spreading the virus that causes yellow fever must have an International Certificate of Vaccination or Prophylaxis (ICVP).

You can find a list of all the countries that require you to have an ICVP (PDF, 436kb) on the WHO website. You can also search the destination information on the NHS Fit for Travel website to find out whether the places you are visiting require an ICVP. An ICVP is not required for entry into the UK.

If you lose your certificate, you may be able to get another one reissued as long as you have details of the vaccination batch number and the date you had the vaccination.

It's always a good idea to keep a photocopy or electronic copy of your ICVP. This will make it simpler to get a replacement certificate if the original certificate is lost or damaged.

Exemption from yellow fever vaccination

Some people may be advised not to have the yellow fever vaccine because of the risk of potential side effects or complications.

This includes:

• babies under nine months of age – babies who are six to nine months old may sometimes be vaccinated, but only if the risk of getting yellow fever during travel is unavoidable
• pregnant and breastfeeding women
• people with weakened immune systems – such as people with HIV and those receiving radiotherapy
• people who are severely allergic to any of the ingredients in the vaccine – including people with allergies to eggs, as the vaccine contains small amounts of egg
• people over 60 years of age - vaccination is often still advised for people in this age group. A careful assessment and discussion about the risks and benefits of the vaccine, and the risk of the disease in the country you are visiting needs to be carried out by a health professional before deciding if you should receive the vaccine or not

If the yellow fever vaccination is not advised, you may be issued with an exemption letter, which may be accepted by immigration authorities.

If you have not been vaccinated, you will need to take particular care to prevent mosquito bites while travelling – for example, by using insect repellent and mosquito nets.

You may be advised not to travel to a country with yellow fever if you are unable to be vaccinated against the disease.

Side effects of the yellow fever vaccine

Up to one in every three people experience mild side effects after having the yellow fever vaccine, such as:

• a headache
• muscle pain
• a mild fever
• soreness at the injection site

Reactions at the injection site usually occur one to five days after being vaccinated. The other side effects may last for up to two weeks.

Rare side effects of the yellow fever vaccine

There are also some very rare, but potentially serious, side effects that can occur, including:

• an allergic reaction to the vaccine; this occurs around once for every 130,000 doses given
• yellow fever vaccine-associated neurological disease (YEL-AND) – a condition affecting the brain and nervous system, causing symptoms such as confusion and problems with movement and co-ordination; this occurs around once for every 250,000 doses given
• yellow fever vaccine-associated viscerotropic disease (YEL-AVD) – a condition affecting your internal organs, which can lead to organ failure in some cases; this occurs around once for every 330,000 doses given

The risk of YEL-AND and YEL-AVD is higher in young babies and elderly people, which is why vaccination is not always recommended for these groups.

If you have recently received the yellow fever vaccine and feel unwell please contact your GP or the NHS 24 111 service if your GP practice is closed.

In a medical emergency, when someone is seriously ill and their life is at risk, dial 999.