BCG Immunisation

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The BCG immunisation (BCG) is now used only for those at most risk of tuberculosis (TB) infection. The BCG is most effective for children aged under 16. It is much less effective for adults. People at highest risk of TB are those who are from countries with a high rate of infection. Areas of the world with high rates of infection include Asia, Africa and Eastern Europe. The BCG is safe and serious side-effects are very rare.

The BCG (bacillus Calmette-Guérin) was introduced into the UK in 1953. It is used to protect against tuberculosis (TB). Over many years the BCG has been shown to be safe. The BCG contains a small number of modified TB germs (bacteria). The BCG stimulates the body defences (the immune system) to be ready to fight TB bacteria. See the separate leaflet called Tuberculosis.

The BCG is also used as part of the treatment for some people who have bladder cancer. See the separate leaflet called Bladder Cancer.

The BCG is thought to give good protection against tuberculosis (TB) for children. It is much less effective for adults. Importantly, the BCG is very good at protecting against the most severe forms of TB, such as TB meningitis in children. Although it is a good immunisation, it does not guarantee protection against TB.

Protection against TB has been shown to last for 10 to 15 years after the BCG when given to children. There is no evidence that repeat vaccination offers any further protection. The  BCG seems to be much less effective when it is given to adults.

Previously, all schoolchildren in the UK were routinely given the BCG at age 13. The policy changed in 2005. Rates of tuberculosis (TB) are now very low in many parts of the country. Children living in these areas have a very low risk of infection. However, in other areas, rates of TB are increasing.

Since 2005, the BCG has been given to those people most at risk of TB infection. The BCG should be give to:


  • All infants (aged 0 to 12 months) living in areas of the UK where there are a high number of people with TB. This usually means some parts of big cities.
  • All infants (aged 0 to 12 months) with a parent or grandparent who was born in a country where there is a high rate of TB infection - eg, Pakistan, Afria, Eastern Europe.
  • Children aged 1 to 15 years who have not already been vaccinated and have a parent or grandparent who was born in a country where there is a high rate of TB infection.
  • Previously unvaccinated children under 16 years of age who are contacts of cases of respiratory TB.
  • Previously unvaccinated children under 16 years of age:
    • Who were born in a country with a high rate of TB infection; or
    • Who have lived for a prolonged period (at least three months) in a country with a high rate of TB infection.

Children aged 6 to 15 years are only given a BCG if a test for TB (Mantoux test) is negative. See the separate leaflet called Tuberculosis for further information on the Mantoux skin test.

Adults in some jobs

People in the following jobs are more likely to come into contact with someone with TB:

  • Healthcare workers who have contact with patients with TB or with some test samples from these patients - eg, blood or phlegm (sputum) tests.
  • Laboratory staff who have contact with patients with TB or with some test samples from these patients - eg, blood or sputum tests.
  • Veterinary and staff such as abattoir workers who handle animal species known to sometimes have TB infection.
  • Prison staff working directly with prisoners.
  • Staff of care homes for the elderly.
  • Staff of hostels for homeless people and centres for refugees and asylum seekers.

People aged under 35 years in these jobs who have not been vaccinated and have a negative Mantoux test are recommended to receive BCG. There is no evidence that the BCG protects adults aged 35 years or older.

Travellers and those going to live abroad

BCG may be needed for people who have not had a BCG and have a negative Mantoux test, depending on where they are going. The BCG is recommended for those aged under 16 years who are going to live or work with local people for more than three months in a country where there is a high rate of TB infection.

The BCG is given as a single injection into the skin of the outside of the upper arm, usually the left arm.

No other immunisation should be given in the arm used to give the BCG for at least three months after the BCG.

The BCG immunisation should not be given to:

  • Those who have already had a BCG immunisation.
  • Those with a past history of tuberculosis (TB) infection.
  • Those with a strong reaction to Mantoux skin testing.
  • Those who have had a confirmed severe allergy reaction to any substance in the BCG.
  • Newborn babies who live in a house where someone has definite or suspected TB infection.
  • People who have reduced body defences (immune system) - eg, those using steroid tablets, those with AIDS or who have cancer.

The BCG can be given if you have a minor illness without a high temperature and are not feeling unwell. If you feel very unwell, the BCG should be delayed until you have recovered. BCG can be given during pregnancy and when breast-feeding. However, it is usually delayed during pregnancy, especially during early pregnancy.

The BCG is very safe. Occasionally reactions can occur at the injection site - eg, infection and scarring. Allergy reactions can occur but are also uncommon.

It is possible for a BCG to cause a tuberculosis (TB) infection in the body but this is very rare.

Further help & information

Original Author:
Dr Colin Tidy
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
28847 (v1)
Last Checked:
Next Review:
The Information Standard - certified member
Now read about Tuberculosis Prevention and Screening

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