This vaccine gives protection against tuberculosis (TB) infection.
It is 70-80% effective against the most severe forms of TB, such as TB meningitis. However, it is less effective in preventing the form of TB that affects the lungs.
The vaccine is usually given to babies and children from birth up to the age of 16 who are identified as being at higher risk of the disease compared to the general population. It is also sometimes given to adults up to the age of 35, but the vaccine does not work well in adults. Adults are often given a skin test before they are offered the vaccine. This is to check whether they already have antibodies to TB (see 'More information about the vaccine' towards the bottom of the page). People with a past history of TB should not receive the vaccine. This is because they have an increased risk of adverse reactions to the vaccine.
In the UK the BCG vaccine is not currently part of the routine childhood schedule. It is offered to people who are at higher risk of TB. The main risk factors for TB are:
Babies and children under 16 in any of these risk groups will usually be offered the BCG vaccine. Adults up to 35 years of age may also be offered the vaccine if their job has a high risk of contact with people or animals infected with TB. However, at the moment there is a worldwide shortage of BCG vaccine (see below). Because of this, in the UK the vaccine is being prioritised for use in new-born babies in areas of highest risk.
The BCG vaccine contains live bacteria that have been weakened (attenuated), so that they stimulate the immune system but do not cause disease in healthy people. However the vaccine should not be given to people who are clinically immunosuppressed (either due to drug treatment or underlying illness). This is because the vaccine strain could replicate too much and cause a serious infection. This includes babies whose mothers have had immunosuppressive treatment while they were pregnant or breastfeeding. For more information see the MHRA's Drug Safety Update (April 2016) .
At the moment there is a serious shortage of the only BCG vaccine licensed for use in the UK. This is because of manufacturing issues at the Statens Serum Institut (SSI) in Denmark, who make the vaccine. In June 2016 the UK Government took the decision to start using an alternative BCG vaccine made by InterVax, a Canadian company. This vaccine is similar to the SSI’s BCG vaccine, but it does not have a UK licence. This does not mean that the vaccine is unsafe or untested. It simply means that the manufacturer, InterVax, has not applied for a licence in the UK, so the vaccine has never formally been approved for use here.
The InterVax BCG vaccine is used in over 100 countries including the Netherlands, France, Belgium, Norway and Sweden. In 2015, over 51 million doses were distributed worldwide. The vaccine has been a World Health Organization (WHO) prequalified vaccine for 25 years. This means it can be used by United Nations organisations for immunisation against TB. The vaccine has a good safety record and is thought to be as effective as the SSI BCG vaccine. For more information see this leaflet from Public Health England .
It is not clear when supplies of the SSI BCG vaccine will be available again. Waiting for a licensed vaccine may mean that babies at high risk do not get vaccinated, and so will be at risk of severe forms of TB. Using the InterVax vaccine means that babies will continue to be protected.
The BCG vaccines used in the UK contain strains of a bacterium closely related to the one that causes TB in humans. The bacterium used for the vaccine is called Mycobacterium bovis, which causes TB in animals such as cows and badgers.
The BCG vaccines used in the UK do not contain the preservative thiomersal (mercury).
Very common side effect (affecting 9 out of 10 people):
Uncommon side effects (between 1 in 1,000 and 1 in 100 people):
Rare side effects (fewer than 1 in 1,000 people):
As with any vaccine, medicine or food, there is a very small chance of an immediate severe allergic reaction called anaphylaxis. Anaphylaxis is different from less severe allergic reactions because it causes life-threatening breathing and/or circulation problems. It is always serious but can be treated with adrenaline. In the UK between 1997 and 2003 there were a total of 130 reports of anaphylaxis following ALL immunisations, but all of these people survived. Around 117 million doses of vaccines were given in the UK during this period, making the overall rate around 1 in 900,000. Depending on the cause of the reaction, and following expert guidance, the person may be able to have vaccinations in the future.
If you are concerned about any of the side effects of the BCG vaccine, consult your GP.
Reactions listed under ‘possible side effects’ or ‘adverse events’ on vaccine product information sheets may not all be directly linked to the vaccine. See Vaccine side effects and adverse reactions for more information on why this is the case.
See more information on the monitoring of vaccine safety.
The tuberculin skin test (also called the Mantoux test) is usually given to people before they are offered the BCG vaccine. If you develop a hard red lump at the test site, this is a positive result. It means that your immune system already recognises TB, because you have been exposed to the disease in the past. In this case you should not be given the BCG vaccine because you already have some immunity to TB, and the vaccine may cause unpleasant side effects. If you have no reaction to the skin test, this is a negative result, and you can safely have the BCG vaccine.
The BCG vaccine was introduced into the UK schedule in 1953. At first it was offered to children of school leaving age (14 years old) because TB was most common in young adults at this time. Rates of TB in the UK were already falling, and they continued to fall after the vaccine was introduced. In the 1960s it was realised that there were higher numbers of TB cases in people coming to the UK from countries with high rates of TB. At this point BCG vaccination was introduced for babies born in the UK to parents from countries with high rates of TB. Vaccination of all children aged 10-14 continued until 2005, when it was decided that TB rates in the general population had fallen to such a low level that universal BCG vaccination was no longer needed. The UK programme now targets babies and children who are most at risk of exposure to TB, with the aim of preventing the more serious childhood forms of TB.
The vaccine is given just under the skin (intradermally), usually in the left upper arm. This is the recommended site, so that small scar left after vaccination can be easily found in the future as evidence of previous vaccination. No other vaccine should be given in the same limb as the BCG for three months afterwards, because of the risk of lymphadenitis (an enlarged lymph node that becomes infected).
BCG stands for ‘Bacillus Calmette-Guérin’, and is named after the two French scientists who developed the first TB vaccine – Albert Calmette and Camille Guérin.