Vaccination is the most effective way of preventing yellow fever.
In the UK, Stamaril (produced by Sanofi Pasteur MSD) is the only licensed yellow fever vaccination.
A single dose of the vaccine provides protection from the yellow fever infection in 95-100% of recipients for at least 10 years.
The current recommendation is that you should have a booster dose every 10 years if you're still at risk of infection. You also need to be able to show proof of vaccination when travelling to an area where there's a risk of yellow fever by showing a valid certificate of vaccination (valid for 10 years from 10 days after the date of vaccination) (see below).
The requirement for a yellow fever vaccination booster is currently under review following a recent statement from the World Health Organization's (WHO) Strategic Advisory Group of Experts (SAGE) on Immunization. They've said that with some exceptions protection lasts for at least 35 years, is likely to be much longer and could be life-long.
However, any changes to the current recommended 10-year period for yellow fever vaccination boosters are unlikely to come into effect until June 2016. The WHO website has more on the latest situation about yellow fever vaccination booster.
Who should be vaccinated?
You should have the yellow fever vaccination if you're:
- a laboratory worker and handle infected material
- nine months of age or over and travelling to a country where you need an International Certificate of Vaccination or Prophylaxis (ICVP) before being allowed into the country (proof of vaccination against yellow fever)
- nine months of age or over and travelling to, or living in, an area or country where yellow fever is found (see risk areas for yellow fever for a list of these areas)
You must have a yellow fever vaccination at least 10 days before you travel. This will allow enough time for your body to develop protection against the yellow fever infection.
Your certificate will only become valid 10 days after you have the yellow fever vaccination.
Where do I get vaccinated?
Yellow fever vaccinations can only be given at designated and registered 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:
Find your nearest yellow fever vaccination centre.
Certificate of proof
Under regulations set out by the World Health Organization (WHO), anyone travelling to a country or area where the Aedes aegypti mosquito is found 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 in the WHO International travel and health guide. You can also search the country information on NaTHNaC to find out whether the places you are visiting require an ICVP.
If you have been travelling in an "at-risk" area during the past month, it is a good idea to carry your certificate with you. This will help avoid potential problems with immigration. It is possible for travellers without a valid yellow fever vaccination certificate to be vaccinated and held in isolation for up to 10 days. 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.
Seeking medical advice
Always consult staff at a designated vaccination centre if you are planning to travel to an area where there is a risk of getting yellow fever. If you tell them where you are travelling to, they will be able to advise you about whether you need to be vaccinated against yellow fever and whether you need an ICVP.
Who should not be vaccinated?
People who should not have the yellow fever vaccination include:
- babies under nine months of age – babies who are six to nine months old should only be vaccinated if the risk of getting yellow fever during travel is unavoidable
- pregnant women – unless the risk of yellow fever is unavoidable
- breastfeeding women – unless the risk of yellow fever is unavoidable
- people whose immune systems are lowered (immunosuppressed) – such as people with HIV and those receiving chemotherapy or radiotherapy
- people who are allergic to eggs – the vaccine contains small amounts of egg
- people who have had a severe allergic reaction (anaphylaxis) to a previous dose of the yellow fever vaccine
- people who are allergic to any of the ingredients in the vaccine
- people who have a condition that affects the thymus gland (part of your immune system that is located in your upper chest)
- people who are currently very unwell (such as with a high fever) – this is to avoid confusing the diagnosis of your current illness with any side effects from the vaccine
- yellow fever naïve travellers – those who have not been previously exposed to the vaccine who are 60 years of age or over (unless the risk of yellow fever is unavoidable)
In cases where having a yellow fever vaccination is not advised, your GP may be able to issue you with an exemption letter. The letter should be written on headed notepaper and include the practice details. It may be accepted by some immigration authorities.
If you are travelling from an area where there is a risk of yellow fever without a valid yellow fever certificate, immigration officials are legally entitled to quarantine you for a period of at least seven days at the point of arrival into a country.
Side effects of the vaccine
After having the yellow fever vaccine, 10-30% of people will have mild side effects such as:
- muscle pain
- soreness at the injection site
- mild fever
Reactions at the injection site usually occur one to five days after being vaccinated, although other side effects may last for up to two weeks.
An allergic reaction to the vaccine occurs in one case out of every 130,000 doses of the vaccine that are given.
Yellow fever vaccine-associated neurological disease (YEL-AND)
Rarely, the yellow fever vaccine is associated with a neurological condition known as yellow fever vaccine-associated neurological disease (YEL-AND). Neurological means that it affects the nerves and the nervous system, including the brain and spinal cord.
YEL-AND occurs in around four cases out of every 1 million doses given. However, for people who are 60 years of age or over and yellow fever vaccine naïve, the incidence of YEL-AND increases to around one in every 50,000. This represents the highest risk for any vaccine currently in use.
The symptoms of YEL-AND include:
- a high temperature (fever) of 38ºC (100.4ºF) or above
- problems with your nerves – for example, a problem with the nerves in your tongue that affects your ability to speak (focal neurological deficit)
- coma (a state of unconsciousness caused by injury or illness)
- Guillain-Barré syndrome (inflammation of the network of nerves that control the body's senses and movements)
Yellow fever vaccine-associated viscerotropic disease (YEL-AVD)
The yellow fever vaccine is also associated with yellow fever vaccine-associated viscerotropic disease (YEL-AVD). Viscerotropic means that it affects the viscera – your internal organs, such as the heart or lungs.
YEL-AVD occurs in around three cases out of every 1 million vaccines that are given. However, for people who are 60 years of age or over and yellow fever vaccine naïve, the incidence of YEL-AVD increases to just over one in every 50,000. This represents the highest risk for any vaccine currently in use.
Symptoms of YEL-AVD include:
- a high temperature (fever) of 38ºC (100.4ºF) or above
- muscle pain
- hepatitis (inflammation of the liver)
- hypotension (low blood pressure)
- multiple organ failure