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BCG (tuberculosis) vaccination


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 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.

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When it is used

If it is advised that your baby has the Bacillus Calmette-Guérin (BCG) vaccine, it is usually offered after birth while your baby is still in hospital.

The BCG vaccine can also be given to older children and adults (see below).

It is given as an injection into the upper arm.

Mantoux (tuberculin) test

A tuberculin skin test, or Mantoux test, should be carried out before the BCG vaccination is given for:

  • all individuals aged six years or over
  • infants and children under six years of age with a history of residence or prolonged stay (more than three months) in a country with an annual TB incidence of 40 per 100,000 or greater
  • those who have had close contact with a person with known TB
  • those who have a family history of TB within the last five years

The Mantoux test checks whether you have a TB infection or disease. This is necessary as many people can become infected with the bacteria that cause TB but do not develop any symptoms (known as latent TB).

The test involves injecting your skin with a substance called purified protein derivative (PPD) tuberculin. If you have immunity to TB, your skin will be sensitive to PPD tuberculin and a hard red bump will develop at the site of the injection, usually within 48 to 72 hours of having the test.

If you develop this reaction (a positive test result), you should not be vaccinated, as the BCG vaccine has no clinical benefit and may cause unpleasant side effects.

If the test proves negative, the BCG vaccine is given.

Who should have the BCG vaccination?

There is little evidence that the BCG vaccine is effective in older people. TB vaccinations are not usually offered to people over the age of 16 unless the risk of exposure is great (for example, if they have come from Sub-Saharan Africa).


BCG vaccination is recommended for all babies who:

  • are born in areas where the rates of TB are high
  • have one or more parents or grandparents who were born in countries with a high incidence of TB

Older children and adults

  • Older children who were not vaccinated against TB when they were babies, and who have an increased risk of getting TB, should be vaccinated.
  • Anyone under 16 who has come from an area where TB is widespread should consider the BCG vaccination (see FAQs below).
  • Anyone under 16 who has been in close contact with someone who has pulmonary TB (TB infection of the lung) should consider the BCG vaccination. 

At-risk occupations

A BCG vaccination is recommended if you are under 35 and work in an occupation with an increased risk of exposure to TB. These people include:

  • laboratory staff who are in contact with clinical materials, such as blood, urine and tissue samples
  • veterinary staff and other animal workers, such as abattoir workers, who work with animals that are susceptible to TB, such as cattle or monkeys
  • prison staff who work directly with prisoners
  • staff of care homes for the elderly
  • staff of hostels for homeless people
  • staff who work in facilities for refugees and asylum seekers
  • healthcare workers with an increased risk of exposure to TB 

Who should not have the BCG vaccination?

The BCG vaccine is not recommended for:

  • people who have already had a BCG vaccination
  • people with a past history of TB
  • people with a positive skin test
  • people who have had a previous anaphylactic reaction (severe allergic reaction) to any of the substances used in the vaccine
  • newborn babies in a household where a case of TB is suspected or confirmed
  • people who have a septic skin condition
  • people who have received another live vaccine less than three weeks earlier
  • people with a weakened immune system, either as a result of a health condition (such as HIV) or treatments such as chemotherapy or immunosuppressant medication (medication that suppresses the immune system)
  • people who have cancer of the white blood cells, bone marrow or lymph nodes, such as leukaemia or lymphoma
  • people who are seriously unwell (vaccination should be delayed until they recover)

Pregnant women and over-16s

TB vaccinations are not usually offered to people aged over 16. Some people over 16 and under 35 whose work puts them at occupational risk should be offered the vaccine (see above). There is limited evidence that the vaccine is effective in those over 16 and virtually no evidence that shows it is effective in those aged over 35.

As a safety precaution, the BCG vaccine is usually not recommended during pregnancy, unless it is thought that the benefits outweigh any possible risks. There have been no recorded reports of the BCG vaccine affecting pregnancy.

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Side effects

Around 90-95% of people will develop a raised blister at the site of the injection immediately after the vaccination. This is normal, and nothing to worry about.

Two to six weeks after the injection, a small spot may appear at the site of the injection. This can be painful for a few days, but should settle. The spot will eventually heal, but it may leave a small scar.

Rarely, some people may have a more severe skin reaction. This should heal within a few weeks.

If you are worried that your skin reaction is abnormal or that the spot may have become infected, contact your GP or telephone NHS Direct Wales on 0845 4647.

Serious side effects, such as an anaphylactic reaction (a serious allergic reaction), are very rare. They occur in less than one in a million cases.

Monitoring safety

In the UK, the safety of vaccines is monitored through the Yellow Card Scheme by the Medicines and Healthcare products Regulatory Agency (MHRA) and the Committee on Safety of Medicines. Levels of disease and vaccine uptake are recorded by the Health Protection Agency to measure the impact of vaccines on disease.

Most reactions reported through the Yellow Card Scheme have been minor, such as rashes, fever, vomiting, and redness and swelling where the injection was given.

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Frequently asked Questions

How does the vaccine work?

Why is TB still a problem?

How common is TB in Wales?

Where in the world is TB widespread?

Is TB contagious?

How do I know if my baby needs the BCG vaccination?

I have an allergy. Could anything in the BCG vaccine trigger that allergy?

Does the BCG vaccine contain any blood products or materials of animal origin?

I live with somebody who has a weakened immune system. If I have the vaccine, is there a risk that the bacteria in the vaccine could infect them?

Why do we no longer vaccinate teenagers with BCG at school? How can I get my child vaccinated?

There was no scar or blister after my child's BCG jab. Did it work? 

How does the vaccine work?

The BCG vaccine contains a strain of mycobacterium bovis, which is a bacterium that causes tuberculosis (TB) in cattle. The bacteria have been altered so that they do not cause a TB infection but make your immune system produce antibodies. These make you immune (resistant) to the disease.

Why is TB still a problem?

It was hoped that with the invention of the BCG vaccine, and associated medications to treat TB, it would be possible to wipe out TB in the same way as smallpox.

This has turned out to be difficult for a number of reasons.

Much of the initial improvement in TB in more developed countries was related to improvements in housing, nutrition and access to treatment. Poor conditions are still present in many less developed countries.

Several strains of TB bacteria have developed a resistance to one or more anti-TB medications, making them much harder to treat. This has been because individuals have not completed the course of treatment or have been prescribed inappropriate treatment, or because the supply of drugs is inadequate.

The BCG vaccination is effective against some severe forms of the disease, such as TB meningitis in children, but it is not effective against all forms of TB.

The global epidemic of HIV that began in the 1980s has led to a corresponding epidemic of TB cases. This is because HIV weakens a person’s immune system, which makes them more likely to develop a TB infection.

TB remains a global health problem and was declared a global health emergency by the World Health Organization in 1993.

The rapid growth and affordability of international travel has allowed people to travel widely and this has contributed to the spread of the disease.

How common is TB in Wales?
TB is uncommon in this country. There were 214 new cases of TB in Wales in 2009.

In 2009, 48% of TB cases reported in Wales were born in the UK, 42% were born abroad and 11% of cases had unknown place of birth.

Cases of TB tend to be concentrated in the larger urban areas such as Cardiff, Newport and Swansea.

Where in the world is TB widespread?
TB is found throughout the world. Parts of the world known to have high rates of TB include sub-Saharan Africa (all the countries south of the Sahara desert) and Asia.

For more information, see the WHO website.

If you are planning to visit a high-risk country and work or live with local people for more than a month, the BCG vaccination is usually recommended.

Is TB contagious?
Yes. TB is spread when a person with an active infection of TB in their lungs coughs or sneezes, and somebody else inhales a droplet of contaminated saliva.

However, TB is not as infectious as the common cold or the flu. You usually need to spend a long time in close contact with an infected person before you catch TB. For example, infections usually spread between family members who are living in the same house.

How do I know if my baby needs the BCG vaccination?
Your midwife, practice nurse and/or GP will be able to tell you if a BCG vaccination is recommended for your baby.

I have an allergy. Could anything in the BCG vaccine trigger that allergy?
No. The BCG vaccine can be used safely by:

  • people who are allergic to latex (a type of rubber)
  • people who are allergic to penicillin
  • people who are allergic to dairy products, eggs and/or nuts

However, if you have any concerns you should talk to your GP before going ahead with vaccination.

Does the BCG vaccine contain any blood products or materials of animal origin?
No. There are no blood products in the vaccine. All of the raw materials used to make the vaccine are from non-animal origins.

I live with somebody who has a weakened immune system. If I have the vaccine, is there a risk that the bacteria in the vaccine could infect them?
No. While the BCG vaccine is not recommended for people with a weakened immune system, they cannot catch TB from someone who has been vaccinated.

Why do we no longer vaccinate teenagers with BCG at school? How can I get my child vaccinated?
TB is a difficult disease to catch because it requires prolonged exposure to an infected person. For example, you are very unlikely to catch it by sitting or standing next to someone who is infected. Also, rates of TB in the indigenous population have fallen to very low levels over the past 15 years.

The BCG vaccination programme was changed to reflect this, following advice from the Joint Committee on Vaccination and Immunisation. The BCG vaccine is now only given to people in at-risk groups (see Who should have it).

If your child does not come into one of the higher-risk groups, the current advice is not to give them the BCG vaccination. There are private clinics that parents can approach for a BCG vaccination, but the NHS does not keep a list of these clinics.

There was no scar or blister after my child's BCG jab. Did it work?
A raised blister will appear in most people (90-95%) who are vaccinated with BCG, but not all. If your child did not have this reaction to the vaccine, it does not mean that they have not responded to it. Vaccinating individuals with BCG a second time is not recommended.

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