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BCG (TB) vaccine FAQs

How well does the vaccine work?

The BCG vaccine contains a weakened strain of TB bacteria, which builds up immunity and encourages the body to fight TB if infected with it, without causing the disease itself.

The BCG vaccination is thought to protect up to 80% of people against the most severe forms of TB for at least 15 years, perhaps even up to 60 years.

Why is TB still a problem?

It was hoped that with the invention of the BCG vaccine and medicines, it would be possible to wipe out TB in the same way that smallpox has been eradicated.

This has turned out to be difficult because:

  • much of the initial improvement in TB rates in more developed countries was related to improvements in housing, nutrition and access to treatment, but these issues are still present in many countries that are less developed
  • several strains of TB bacteria have developed resistance to 1 or more anti-TB medications, making them much harder to treat
  • the BCG vaccination is effective against severe forms of the disease, such as TB meningitis in children, but it's not as 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 because HIV weakens a person's immune system, making them more likely to develop a TB infection
  • the rapid growth of international travel has helped the infection to spread

How common is TB in the UK?

TB is not very common in the UK. There were 5,102 cases of TB in England in 2017.

Rates of TB are higher in some communities of people who were not born in the UK. This is largely because of their connections to areas of the world where rates of TB are high.

Is TB contagious?

Yes. TB is spread from one person to another through tiny droplets released into the air when a person with TB coughs or sneezes and somebody else breathes in these droplets.

But TB is not as easy to catch as the common cold or flu. You usually need to spend a long time in close contact with an infected person (with TB in their lungs or throat) before you catch TB.

For example, infections usually spread between family members who are living in the same house.

TB cannot be spread through touch or sharing cutlery, bedding or clothes.

Find out how you catch TB

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

Your midwife, practice nurse or GP can tell you if a BCG vaccination is recommended for your baby.

The NHS leaflet: TB, BCG and your baby (PDF, 191kb) has more information.

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

No. The BCG vaccine is safe for:

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

But if you have any concerns, talk to a GP or practice nurse 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.

Read the patient information leaflet for the BCG AJV vaccine (PDF, 272kb)

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

No. Vaccination with BCG reduces the risk of TB and therefore also reduces the risk of TB being transmitted to people with a weakened immune system.

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 the BCG at school?

The BCG is no longer offered to children in secondary schools in the UK. It was replaced in 2005 with a targeted programme for babies, children and young adults at higher risk of TB.

This is because TB rates in this country are low in the general population.

TB is difficult to catch because this requires close contact with an infected person, usually over a long period of time.

For example, you're very unlikely to catch it by sitting or standing next to someone who's infected.

Find out who should have the BCG vaccine

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

A raised blister will appear in most people vaccinated with BCG, but not everyone.

If your child did not have this reaction to the vaccine, it does not mean that they have not responded to it. There's no need to vaccinate with BCG a second time.

Page last reviewed: 23 April 2019
Next review due: 23 April 2022