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 TB itself.
BCG vaccination given to babies and young children provides consistent protection (up to 80%) against severe forms of childhood TB, such as TB meningitis. It can be less effective against TB affecting the lungs in adults.
The protection from the BCG vaccine can last up to 15 years.
Why is TB still a problem?
It was hoped that with the invention of the BCG vaccine and medicines against TB, 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 medicines, 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 TB affecting the lungs in adults, so the impact of BCG vaccination on the spread of TB is limited
- 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 TB and other infections
- 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. In 1950s, in the UK, there were over 50,000 new cases of TB every year. Today, this number has dropped to just over 5,000 new cases a year.
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 measles, 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, TB is usually caught from family members or friends who are living in the same house.
TB cannot be spread through touch or sharing cutlery, bedding or clothes.
How do I know if my baby needs the BCG vaccination?
Your midwife, health visitor, 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 midwife, health visitor, 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.
I live with somebody who has a weakened immune system. If I have the vaccine, is there a risk that I could infect them?
The BCG vaccine does not give you TB. If you live with someone who has a weakened immune system, you cannot give them TB from having the vaccine.
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 very low in the general population.
TB is difficult to catch because this requires close contact with an infected person (for example, living together).
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