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.

TB 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 as the vaccine gives good protection against TB.

Who should be immunised against TB?

The immunisation programme to counter TB has changed over the past few decades as the number of people with TB has reduced in many parts of the UK. Immunisation with BCG vaccine is now only given to those people, usually children, who are at a high risk of catching TB. This has changed from 2005. Before 2005 all children were routinely immunised with the BCG vaccine at the age of 13 years.

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 (and children who have not previously been immunised) whose parents or grandparents have lived in a country 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:
  • Children (under 16 years) who have come to live in the UK from countries where TB is common (at least 40 cases per 100,000 people per year) and have not been immunised before.
  • Adults under 35 years who have come to live in UK from countries where there is a high rate of TB - over 500 cases per 100,000 people per year.
  • People at risk due to their job. For example, health workers, prison staff, etc.
  • Close contacts of people with active TB who have never received the BCG vaccine.

Rates of TB are now very low in many parts of the UK 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 immunisation with BCG vaccine through the schools' programme are now screened for risk factors for TB, tested, and immunised as appropriate.

Tuberculin testing

Before being immunised with BCG vaccine, the tuberculin test is usually done. A few days before the 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 previously been immunised with BCG vaccine. 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 vaccine 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 before immunisation with the BCG vaccine 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 where there 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 bacteria in the BCG vaccine are still alive but weakened so they can not cause TB. The injection is usually given into the left upper arm. As the vaccine is only effective in about 8 in 10 people, it does not guarantee protection against the TB. Some people still develop TB even if they have had been immunised with 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 scab with a bandage unless it oozes. If this happens you can use a dressing just until the oozing stops. After several weeks the scab goes and you are usually left with a small scar.

Are there any possible side-effects from the BCG vaccine?

• 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 simply a natural reaction to the vaccine.
• A severe allergic reaction to BCG is extremely rare.

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

Who should not be immunised with the BCG vaccine?

You should not have the BCG vaccine:

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

Further information

Information on immunisation from the NHS

Web: www.immunisation.org.uk