BCG TB vaccine: frequently asked questions

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 for up to 15 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 for a number of reasons:

  • 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 a resistance to one 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 is 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. This is 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 disease to spread.

How common is TB in the UK?

TB isn't very common in the UK. There were 6,240 cases of TB in the UK in 2015. Rates of TB are higher in some communities of non-UK born people. 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 when a person with TB in their lungs or throat, coughs or sneezes and somebody else breathes in the droplets of saliva containing the infection.

However, TB is not as infectious as the common cold or 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.

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

Read about 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.

This NHS leaflet: TB, BCG and your baby (PDF, 289kb) 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 and/or nuts

However, if you have any concerns, 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 I 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 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. 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.

Read about 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.

I've heard there's a shortage of the BCG vaccine. How will this affect my baby?

There have been problems with the supply of the usual BCG vaccine given in England. To protect those babies at high risk of developing TB, Public Health England has secured a supply of an alternative BCG vaccine.

This vaccine, made by InterVax, has been approved by the World Health Organization (WHO) and is used extensively around the world.

The InterVax BCG vaccine is given in exactly the same way as other brands of BCG vaccine. 

For more information about the InterVax BCG vaccine, talk to your doctor, nurse or midwife. There is also a leaflet about this vaccine (PFD, 194kb) for you to read.

Page last reviewed: 26/04/2016
Next review due: 31/01/2019