What is yellow fever?

Yellow fever is a serious disease caused by a virus. For some people it can cause a flu-like illness which improves completely. However, for other people it causes symptoms of high fever, vomiting, jaundice and bleeding which can be fatal. There is no cure for yellow fever.

Yellow fever is passed to humans by bites from infected mosquitoes which tend to bite during daylight hours. (This is different to the mosquitos which carry malaria which tend to bite from dusk to dawn.) Yellow fever occurs in certain countries of tropical Africa and South America.

Who should be immunised against yellow fever?

• Travellers over the age of nine months to countries where yellow fever is a risk. Some countries require an International Certificate of Vaccination against yellow fever before they will let you into the country. Yellow fever is the only disease which routinely requires proof of immunisation:
  • In some countries immunisation is compulsory for all incoming visitors.
  • In some countries immunisation is compulsory for those who have travelled from a 'yellow fever' area or country.
  • Your doctor or practice nurse can advise if you should be immunised for your travel destination and whether you need this certificate of immunisation.
• Workers who handle material that may be infected by the yellow fever virus. For example, laboratory workers.

The vaccine and where can I get it?

You should have an injection of vaccine at least ten days before the date of travel to allow immunity to develop. A single dose of vaccine provides immunity for at least 10 years, maybe even for life. However, a booster dose (and a repeat certificate of immunisation) is recommended every 10 years if you are still at risk.

Yellow fever vaccine can only be given at accredited centres. Many GP practices are accredited. If your local GP practice is not accredited you can find a list of the nearest available centres at www.nathnac.org.

The vaccine stimulates your body to make antibodies against the yellow fever virus. These antibodies protect you from illness should you become infected with this virus. The yellow fever vaccine can be given at the same time as other vaccines.

Are there any possible side-effects from the vaccine?

Up to 3 in 10 people who are immunised with yellow fever vaccine have mild headache, muscle aches, mild fever or soreness at the injection site. These symptoms can last up to 14 days after the injection. Severe reactions are very rare, but the risk increases in older people.

Who should not receive the yellow fever vaccine?

The yellow fever vaccine is not usually given under the following circumstances, although advice should be taken from your doctor or practice nurse.

• If you cannot have the yellow fever vaccination and will be travelling to areas where yellow fever occurs cannot be avoided, you will still need advice about yellow fever, certificates to travel and how to avoid mosquito bites.
• If you have reduced immunity (people with HIV, those taking high dose long-term steroids, those receiving chemotherapy, etc)
• If you are ill with a fever you should postpone the injection until you are better.
• As a rule, pregnant women should not be immunised with this vaccine. It is sometimes given after the 6th month of pregnancy if you are at a high risk of catching yellow fever. This vaccine may be given if you are breastfeeding and cannot avoid being at high risk of catching yellow fever.
• You should not have the yellow fever vaccine if you have had a severe (anaphylactic) reaction in the past to egg. (This is because the vaccine contains small amounts of egg. A severe reaction to egg is very rare and it does not mean an upset stomach eating eggs or disliking eggs.)
• Children under 9 months old should not receive the yellow fever vaccine. (Babies aged 6-9 months may occasionally receive the vaccine if the risk of yellow fever during travel is unavoidable.)
• Older travellers (those aged over 60 years) who have not previously been vaccinated against yellow fever are at a higher risk of side effects with the yellow fever vaccine.
• If you have had a severe reaction to the yellow fever vaccine in the past.
• If you have a thymus disorder.