BCG Immunisation

What is tuberculosis?

Tuberculosis (TB) is an infection caused by a bacterium (germ) called Mycobacterium tuberculosis. It is a major cause of illness world-wide. Although it can affect any part of the body, the common illness is a lung infection. It is often passed from family members to each other through coughing. If you get TB, treatment is available. However, the treatment is not easy and prevention is best. In the UK, the main impact on preventing TB was made by better housing and sanitation conditions over the last 80 years or so. Immunisation has also played a role in preventing TB.

In the UK, immunisation against TB with the BCG vaccine is offered to:

• Babies living in areas of the UK where there is a high rate of TB. That is, areas where the incidence of TB is 40 cases per 100,000 people per year, or greater.
• Babies whose parents or grandparents have lived in a country with a high rate of TB. That is, countries where the incidence of TB is 40 cases per 100,000 people per year, or greater.
• The following groups of people who have not previously been immunised.
  • Immigrants to the UK from countries where TB is common.
  • People at risk due to their job. For example, health workers, prison staff, etc.
  • Close contacts of people with active TB.
  • People who intend to live for one month or more in countries with a high TB rate.

Note: until 2005, all schoolchildren in the UK were routinely given the BCG vaccine at about the age of 13. The policy changed in Autumn 2005 and those now immunised are in the groups listed above. The policy change was due to the changing patterns of TB in the UK. Rates of the disease are now very low in many parts of the country and children living in these areas have a very low risk of infection. However, in other areas, rates of TB are increasing. This is why the BCG vaccine is now mainly targeted at babies living in areas where there is an increasing rate of TB cases. Your doctor or midwife will be able to tell you if you live in an area with a high rate of TB.

Children who would previously have been offered BCG through the schools' programme will now be screened for risk factors, tested and immunised as appropriate.

Tuberculin testing

Before being immunised with BCG vaccine, the tuberculin test is commonly done (but not always - see below). A few days before the BCG immunisation an injection is given into the skin of part of the TB germ. The injection site is examined a few days later. In brief:

• If there is no reaction to the tuberculin test it means that you have not been in contact with TB and have not had a previous BCG immunisation. You should then be immunised.
• If a positive reaction occurs (the skin becomes red and inflamed), this can mean:
  • previous infection with TB, or
  • current infection with TB, or
  • previous immunisation with BCG which has been forgotten.

You should not be immunised if you have a positive tuberculin test. You may be advised to have tests to see if you have active TB.

A tuberculin skin test is not necessary prior to BCG vaccination for children up to and including five years of age provided that:

• The child has not lived in (or visited for more than a month) a country with a high TB rate. That is, countries where the incidence is 40 cases per 100,000 people per year, or more.
• The child has not been in contact with a person who is known to have active TB.

The BCG vaccine

The BCG vaccine (Bacillus Calmette-Guerin) was introduced into the UK in 1953. The vaccine has modified small amounts of the TB bacterium. The injection is usually given into the left upper arm. The vaccine is thought to give more than 70% protection against TB. So, although it is a good vaccine, it does not guarantee protection against TB. Some people still develop TB even if they have had the BCG vaccine.

After having the injection, it is normal to develop a red lump over the injection site. This may increase in size for a few weeks before settling down into a scab. It is not necessary to cover the site with a bandage unless it oozes. If this happens, use a dressing just until the oozing stops. After several weeks the scab goes and you are left with a small scar.

Are there any possible side-effects from BCG immunisation?

• In some people, the skin reaction is more severe. However, most reactions settle down over a few weeks.
• Rarely, a larger than normal scar develops.
• Some glands in the nearby armpit may swell a little. This is a natural reaction to the vaccine and of no concern.
• Rarely, a severe allergic reaction to BCG occurs soon after the injection. This may cause redness and swelling of the face, throat or neck, skin rash, and breathing difficulties.

See a doctor if you have concerns about any reactions following immunisation.

You should not have BCG immunisation:

• If your immune system is not working properly. For example, if you are having chemotherapy or radiotherapy, or have a condition such as leukaemia or cancer, or you are taking high doses of steroids, or if you are HIV positive.
• If you are pregnant.

Further information

Information on immunisation
www.immunisation.org.uk
From the NHS aimed at the general public.

Immunisation Against Infectious Disease (The Green Book)
www.dh.gov.uk/PolicyAndGuidance/HealthAndSocialCareTopics/GreenBook/fs/en
From the Department of Health. Aimed at health professionals but of interest to all.

© EMIS and PIP 2005   Updated: November 2005   PRODIGY Validated