TB, BCG vaccine and your baby

Updated 18 April 2023

Applies to England

This leaflet is about the Bacillus Calmette-Guérin (BCG) vaccination that is being offered to protect your baby against tuberculosis (TB).

The BCG vaccine

BCG vaccine contains a weakened form of the bacteria (germ) that causes TB. Because it is weakened it doesn’t cause TB, but it helps your baby develop protection (immunity) against TB in case he or she ever meets it.

The BCG vaccination is particularly effective in protecting babies and young children against the rarer severe forms of TB such as TB meningitis (swelling of the lining of the brain).

TB infection

TB is a bacterial infection; it usually affects the lungs but can also affect any part of the body. Infection with the TB germ may not develop into TB disease. TB disease develops slowly in the body, and it takes several months for symptoms to appear.

Most people who have TB infection will never develop TB disease. In these people, the TB germ remains inactive for a lifetime. In other people (for example, those who have weak immune systems), the TB germ may become active and cause TB disease. Most people in this country recover fully after treatment, but this takes several months.

Treating TB takes a long time. Preventing it is much easier.

Symptoms of TB

TB can affect any part of the body. The symptoms will vary and the signs of disease in a baby may be different from those of an adult. As TB is infectious, it is important that you can recognise the disease in someone else.

You should contact a doctor if you, your baby, or any other member of your family, or a friend has any of the following:

  • persistent cough that lasts for more than 2 weeks fever
  • sweating, especially at night
  • unexplained weight loss
  • failure for a baby to put on weight
  • a general and unusual sense of tiredness and being unwell
  • coughing up blood

How TB is caught

You can only catch TB from someone whose lungs or throat are already infected and who is coughing. When they cough, a spray of tiny droplets is produced that contain the bacteria. If someone breathes in the droplets they too can catch the infection. It takes sharing of an enclosed space with an infected person, for example living in the same house, to be at risk of being infected.

How common TB is

In the UK in the 1950s, 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. So, while it is unlikely that you will get infected, everybody should be aware of the symptoms of TB.

This is especially important because TB is a widespread disease worldwide.

The risk of disease is higher in people who have lived or worked in countries with high rates of TB. Children from these families are also more likely to have close contact with infected members of their community, either in the UK or in their country of origin.

Why your baby is being offered BCG

In the UK, like many other countries, BCG is offered to babies who are likely to spend time with someone with TB. This includes babies who live in an area with high rates of TB or babies with parents or grandparents from a country with high rates of TB.

How your baby is immunised

Your baby will be given the BCG vaccination in the upper part of the left arm.

The vaccination is given soon after birth, usually by 28 days after birth.

Side effects

Immediately after the injection, a raised blister will appear. This shows that the injection has been given properly.

Within 2 to 6 weeks of the injection a small spot will appear. This may be quite sore for a few days, but it should gradually heal if you don’t cover it. It may leave a small scar. This is normal.

Occasionally, your baby may develop a shallow sore where they had the injection. If this is weeping fluid and needs to be covered, use a dry dressing – never a plaster – until a scab forms. This sore may take as long as several months to heal.

If you are worried or you think the sore has become infected, see your doctor.

Reasons why your baby shouldn’t have the BCG vaccination

As with most other immunisations, the injection may not be given or should be delayed if:

  • your baby has a high fever
  • your baby is suffering from a generalised infected skin condition. If eczema is present, an injection site will be chosen that is free from skin lesions

Rarely, in children who have weakened immune systems, the bacteria in the vaccine can cause serious infection.

It is very important that you tell the nurse or doctor if your child has, or is suspected of having, a weakened immune system. For example:

  • the child is on treatment for cancer or other serious conditions
  • the child’s mother had immunosuppressive biological therapy in pregnancy
  • there is a family history of problems with the immune system (for example HIV, Severe Combined Immunodeficiency (SCID))
  • babies who have or might have SCID

Which babies need to have BCG

Even if you don’t live in an area where all babies are offered BCG your baby may still need the vaccine.

If you answer ‘Yes’ to any of the following questions, you should ask your doctor or nurse about BCG for your baby:

  1. Does your baby, the baby’s mother, father or grandparents, or anyone who lives with you, come from a country with a high rate of TB?

  2. Will you and your baby be going to live or to stay with friends and family in one of these countries?

  3. Does anyone who lives with you, or who spends a lot of time with your baby, have TB now or had TB in the past?

BCG and routine immunisations

Your baby can start their routine immunisations at 8 weeks of age regardless of when they have their BCG. You should make sure that your baby is not given another injection in the same arm as the BCG for at least 3 months afterwards; otherwise the glands in that area may swell.

Make sure that there is a record of the BCG vaccination in your child’s Personal Child Health Record (Red book) for future reference.

Further information

If you want more information on TB, or the BCG vaccine or any other immunisations, speak to your doctor, health visitor, midwife or nurse – or visit NHS.UK.