BCG vaccine

Also called TB vaccine

The BCG vaccine helps protect against severe forms of tuberculosis (TB). Find out about the vaccine and possible side effects.

What is the BCG vaccine?

The BCG (Bacillus Calmette-Guérin) vaccine helps protect against severe forms of tuberculosis (TB) by helping your immune system fight against TB. TB is an infectious disease that can cause tiredness, coughing, fever and shortness of breath. Read more about TB. 

Children under 5 years can be protected from severe forms of TB with a free BCG vaccination if they are at risk of catching the disease. The vaccine will not prevent a person becoming infected with tuberculosis. However, when BCG vaccine is given just after birth, 7 out of 10 of infants and young children will be protected from developing severe forms of TB, e.g. meningeal TB (affecting the brain) and miliary TB (widespread).

Who should get the BCG vaccine?

BCG vaccine is not recommended for the general population because the rates of TB are quite low in many parts of the country. The vaccine is more effective when given to children, and seems to be much less effective when it is given to adults.

BCG vaccination is recommended for babies or children less than five years of age if they have a higher risk of getting TB, such as if they:

  • will be living in a house or family/whānau with a person with either current TB or a history of TB
  • have one or both parents or household members or carers who, within the past 5 years, lived for a period of 6 months or longer in countries with a high TB rate. As a general indication, the following areas have high rates of TB:
    • most of Africa
    • much of South America
    • Russia and the former Soviet states
    • the Indian subcontinent
    • China, including Hong Kong and Taiwan (ROC)
    • South East Asia (except Singapore)
    • some Pacific nations (except the Cook Islands, Niue, Samoa, Tokelau and Tonga).
  • will be living for three months or longer in a country with a high TB rate and are likely to be exposed to those with TB.

When is the best time for my child to have the BCG vaccine?

It is best for your child to have the vaccine within a few days of being born and up to 6 months old, but they can be vaccinated any time up to 5 years of age. If your child is older than 6 months, he or she will be tested first to see if they have TB. Depending on the results of this test, your child may be offered the BCG vaccine. Read more about tuberculin skin test.

How effective is the BCG vaccine?

BCG immunisation is partially protective against tuberculosis infection.

  • When the BCG vaccine has been given just after birth 59% of infants and young children will be protected from developing pulmonary TB (TB of the lungs) and 90% from severe forms of TB such as meningeal TB (infection of the membranes covering the brain).
  • Protection has been shown to last for up to 20 years after BCG immunisation.

Who should not get the BCG vaccine?

The BCG vaccine should not be given to adults and anyone with severe allergy (anaphylaxis) to a previous dose of this vaccine. The BCG vaccine should not be given to children:

  • over the age of 5 years
  • who have a weakened immune system, eg, if they are taking medicines that weaken the immune system, are getting radiotherapy or have some cancers
  • who have infected skin conditions. When eczema is present, an immunisation site not affected by the eczema should be chosen.

For children who have a fever over 38°C, administration of BCG vaccine should be postponed until the fever resolves. The presence of a minor infection is not a reason to delay immunisation.

How is the BCG vaccine given?

The BCG vaccine is given as an injection under the skin on the upper arm. It is usually given as one dose. There is no need for a second dose.

Note: only gazetted BCG vaccinators are able to administer the BCG vaccine. Contact your local public health service to find out who can give the BCG vaccine in your area. For example, see the Auckland Regional Public Health Service website to find out if your child is eligible for the BCG vaccination. 

What to expect after the vaccination  

Skin reactions to the BCG vaccine are common, but serious long-term problems are rare. Most children develop a sore at the injection site. Once healed, the sore may leave a small scar.

  • In 1 to 6 weeks, a small red blister may appear where the injection was given.
  • After 6 to 12 weeks, the blister may turn into a small, weeping sore. If this happens, cover the site with gauze to allow air to get in. Do not use sticking plasters.
  • The sore may take up to 3 months to heal and may leave a small scar. This is normal.

How to care for the vaccination site

  • Keep the site clean and dry.
  • If a sore develops, cover the site with gauze to allow air to get in.
  • Do not squeeze or scratch the site.
  • Do not use ointments, oils or herbs on the site.
  • Do not put a sticking plaster over the site.
  • Do not rub or massage the site.

Learn more

The following links provide further information on BCG vaccine:

References

  1. Tuberculosis Immunisation Handbook, NZ, 2017
  2. BCG Vaccine SSI The Immunisation Advisory Centre, NZ, 2018
Credits: Sandra Ponen, pharmacist. Reviewed By: Dr Ayesha Verrall, Senior Lecturer, Department of Pathology and Molecular Medicine, University of Otago, Wellington (Sept 2018) Last reviewed: 23 Sep 2018