Yellow Fever

What is Yellow Fever?

Yellow fever is caused by a viral infection transmitted by certain mosquitos. The virus affects humans and other primates such as monkeys and apes. It is a severe disease with a high risk of complications and death. Many countries that do not yet have Yellow Fever but do have mosquitos that could carry the virus place restrictions on travellers who have been to areas where the infection is found. These restrictions ensure that the travellers are immunised and cannot bring the Yellow Fever virus into those countries.

Because of the risk of spreading Yellow Fever and the restrictions placed on travellers by these countries all travellers to areas with a risk of Yellow fever must be able to show a certificate to prove they have been vaccinated or have a medical contraindication to vaccination. Yellow fever vaccines and certificates can only be issued by approved centres.

Where is Yellow fever found?

At present it is only found in certain countries in tropical areas of Africa and South America. Because mosquitos transmit it, the risk may change over time in certain areas so it is important to have up-to–date information. Your overall risk for yellow fever infection relates to where you will be and what you are doing in the countries you travel through. Once you have a clear idea of you travel itinerary you should discuss the requirement for yellow fever with a travel doctor. You should aim do this as early as possible. Yellow fever immunity takes at least 14 days after vaccination to be affective or accepted for countries imposing travel restrictions. Many of the countries that have risk of yellow fever also have risks for other illnesses so often other vaccines or treatments may be advised. To allow plenty of time for these you should see the Doctor at least 8 weeks before you intend to depart.

Vaccination for Yellow fever

Yellow fever vaccination can only be given at approved centres.

It is a live-attenuated vaccine, this means the vaccine contains a strain of Yellow Fever Virus that seldom causes illness. It is thought to give lifelong immunity though some countries have previously required a booster after 10 years.

Yellow fever vaccination may cause some side effects. As with all vaccines local reactions at the injection site are common. The risk of serious allergic reactions is very small much as for most vaccines. In very rare cases yellow fever vaccination may cause illness similar to the yellow fever illness with risk of complications and very occasionally death.

People older than 60 years are more at risk of complications, as are those with diseases or on medications that suppress their immune system. In these people the risks of Yellow fever need to be carefully weighed up against the risk of vaccinations. Yellow fever vaccine has been used safely in pregnancy though generally we avoid live vaccines if possible at that time. Certainly the complications of the disease may be more severe in pregnancy.

Yellow fever vaccine cannot be given to children under 6 months of age.

Those people who have a medical condition that would prevent them having the vaccine need to seriously consider the risks of their trip. A medical Waiver for Yellow fever vaccine may be issued by the certified Doctor if appropriate.

Consult your doctor early about the need for Yellow Fever vaccination on your trip.