What is tick-borne encephalitis?

Tick-borne encephalitis (TBE) is caused by a virus. It is usually spread by bites from ticks which are infected with the virus. Unpasteurised milk from infected animals, especially goats, is a less common source of the infection. Affected people often develop a flu-like illness that lasts about a week. This may then progress to encephalitis (brain inflammation) or meningitis (inflammation of the tissues around the brain) which can cause headache, fever, confusion, agitation, vomiting and can lead to a coma or even death.

There are three different types of tick-borne encephalitis virus: Western European TBE virus, Far Eastern TBE virus and Siberian TBE virus. Western European TBE occurs mainly in western and central European countries and is particularly common in forest and mountainous regions. Far Eastern TBE occurs in eastern Russia and some countries in East Asia, particularly in forested regions of China and Japan. Siberian TBE occurs in Siberia.

Who should be immunised against tick-borne encephalitis?

Your doctor or practice nurse can advise if you should have this immunisation for your travel destination.

Generally, the risk to the average traveller to affected countries is small. Immunisation is recommended for people who intend to walk, camp or work in heavily forested regions of affected countries between April and October when the ticks are most active. In particular, if you stay in areas where there is heavy undergrowth. It is also recommended for people who handle material that may be infected by the virus (for example laboratory workers).

The vaccine schedule

The usual schedule is to have three injections of vaccine. The second vaccine is given 1-3 months after the first and the third is given 5-12 months after the second. You should have booster doses every three to five years if you continue to be at risk of infection. If you are over 60 years old the booster should be given every three years. If immunity is required more quickly, then a second dose can be given two weeks after the first dose which gives slightly less protection than the other schedule.

The vaccine stimulates your body to make antibodies against the virus. These antibodies protect you from illness should you become infected with this virus.

Who should not receive the tick-borne encephalitis vaccine?

• If you are ill with a fever you should postpone the injection until you are better.
• You should not have a booster if you have had a severe reaction to this vaccine in the past.
• You should not have this vaccine if you have a severe allergy to egg. (This is because the vaccine contains small amounts of egg protein. Allergy to egg is rare and it does not mean an upset stomach when you eat eggs or disliking eggs.)
• The vaccine is not licensed for children under the age of three years.
• This vaccine is safe to give if you are pregnant or breast feeding.

Are there any possible side-effects from the vaccine?

• Mild pain and redness occur at the site of injection in some people.
• Tiredness, mild fever, feeling sick and an itchy rash and headache occur for 1-2 days in some people following injection of the vaccine.
• Severe reactions are extremely rare.

You should also try to prevent tick bites and infection

Immunisation is usually effective, although not 100% effective in all cases. So, if you are travelling to affected areas, whether you have been immunised or not, it is also important to:

• Cover arms, legs and ankles.
• Use insect repellent on exposed skin, socks and outer clothing.
• Not drink unpasteurised milk, especially goats milk.

Any ticks which do attach should be completely removed as soon as possible, preferably slowly and without twisting, with tweezers.

Further information

Information on immunisation from the NHS

Web: www.nhs.uk/Planners/vaccinations/Pages/Travelvaccines.aspx

Health Advice for Travellers.

All travellers going abroad are advised to get this booklet by the Department of Health. You can get a free copy from main post offices.

Patient UK Travel Health Page

Web: www.patient.co.uk/showdoc/38
Has a comprehensive list of links to UK websites on travel health.

References

• Heinz FX, Holzmann H, Essl A, et al; Field effectiveness of vaccination against tick-borne encephalitis. Vaccine. 2007 Oct 23;25(43):7559-67. Epub 2007 Aug 31. [abstract]
• Immunisation against infectious disease - 'The Green Book', Dept of Health (various dates)
• Immunizations - travel vaccinations, Clinical Knowledge Summaries (2007)