Last updated: 04 October 2011
The Bacillus Calmette-Guérin (BCG) vaccine provides protection against tuberculosis (TB).
TB is an infection caused by a bacterium called mycobacterium tuberculosis.
The most common form of TB in the UK affects the lungs, but it can affect other parts of the body such as the bones, joints and kidneys. It can also cause meningitis.
TB can be a very serious disease, but with effective treatment it is possible to make a full recovery from most forms of TB.
For more information, see the Health A-Z topic about TB.
Who should have the vaccine?
The BCG vaccine is not given as part of the routine childhood vaccination schedule unless a baby is thought to have an increased risk of coming into contact with TB.
For example, all babies born in some areas of inner-city London (where TB rates are higher than in the rest of the country) should be offered the BCG vaccination.
BCG vaccinations may also be recommended for people who have an increased risk of developing TB, such as:
- health workers
- people who have recently arrived from countries with high levels of TB
- people who have come into close contact with somebody infected with respiratory TB
About the vaccine
The BCG vaccine is made from a weakened form of a bacterium closely related to human TB. Because the bacterium is weak, the vaccine does not cause any disease but it still makes the immune system produce antibodies, which makes people who receive it immune to TB.
The BCG vaccine does not contain mercury.
The vaccine is 70-80% effective against the most severe forms of TB, such as TB meningitis in children. It is less effective in preventing respiratory disease, which is the more common form in adults.
Continue to next section: When the BCG vaccination is offered