The Bacille Calmette-Guerin (BCG) vaccine offers limited protection against tuberculosis (TB). In the UK it is given to high-risk infants. Until 2005 it was also routinely given to children at the age of 13 years.

The BCG vaccine does not prevent primary infection with tuberculosis or prevent the reactivation of latent TB. It does not provide reliable protection against any forms of TB in adults. It is still used because it is protective against severe diseases in children, particularly TB meningitis and disseminated TB in children. It is thought to prevent 60 - 80% of cases of TB meningitis in children who received BCG as neonates.

The Greenbook currently advises that the vaccine is administered to the following groups (below is summary, please see the link for more details):

• all infants (aged 0 to 12 months) living in areas of the UK where the annual incidence of TB is 40/100,000 or greater
• all infants (aged 0 to 12 months) with a parent or grandparent who was born in a country where the annual incidence of TB is 40/100,000 or greater. The same applies to older children but if they are 6 years old or older they require a tuberculin skin test first
• previously unvaccinated tuberculin-negative contacts of cases of respiratory TB
• previously unvaccinated, tuberculin-negative new entrants under 16 years of age who were born in or who have lived for a prolonged period (at least three months) in a country with an annual TB incidence of 40/100,000 or greater
• healthcare workers
• prison staff
• staff of care home for the elderly
• those who work with homeless people

The vaccine contains live attenuated Mycobacterium bovis. It also offers limited protection against leprosy.

Administration

• any person being considered for the BCG vaccine must first be given a tuberculin skin test. The only exceptions are children < 6 years old who have had no contact with tuberculosis
• given intradermally, normally to the lateral aspect of the left upper arm
• BCG can be given at the same time as other live vaccines, but if not administered simultaneously there should be a 4 week interval

Contraindications

• previous BCG vaccination
• a past history of tuberculosis
• HIV