BCG vaccine SSI

How does it work?

The BCG vaccine contains a live but weakened form of Mycobacterium bovis, which is the bacterium that causes tuberculosis (TB). (The vaccine is known as BCG because a strain of the bacterium known as Bacillus Calmette-Guerin is used). The vaccine is used to prevent tuberculosis, and works by stimulating the body's immune response to the bacteria, without actually causing the disease.

When the body is exposed to foreign organisms, such as bacteria and viruses, the immune system produces antibodies against them. Antibodies help the body recognise and kill the foreign organisms. The antibodies remain in the body to help protect the body against future infections with the same organism. This is known as active immunity.

The immune system produces different antibodies for each foreign organism it encounters. This establishes a pool of antibodies that helps protect the body from various different diseases.

Vaccines contain extracts or inactivated forms of bacteria or viruses that cause disease. These altered forms of the organisms stimulate the immune system to produce antibodies against them, but don't actually cause disease themselves. The antibodies produced remain in the body so that if the organism is encountered naturally, the immune system can recognise it and attack it. This prevents it from causing disease.

Each bacteria or virus stimulates the immune system to produce a specific type of antibody, and this means that different vaccines are needed to prevent different diseases.

The BCG vaccine stimulates the immune system to produce antibodies against Mycobacterium tuberculosis bacteria. This provides immunity against tuberculosis. The vaccine is given as one dose by injection into the skin of the upper arm. The length of time that the immunity lasts is not known, but revaccination is not recommended.

The vaccine is no longer given to all children as part of the schools vaccination programme. Instead there is now an improved programme of targeted vaccination for those individuals who are at greatest risk of contracting the disease. The main risk groups are infants under one year of age living in areas where the incidence of TB is 40 cases per 100,000 people or higher, infants under one year of age whose parents or grandparents were born in a country with an incidence of TB of 40 cases per 100,000 people or higher, and new immigrants from countries with a high incidence of TB who have not already been vaccinated.

Children who would previously have been vaccinated through the schools programme will now be screened for risk factors for TB and only given the vaccine if they are at risk. Other high risk groups who are recommended vaccination are: contacts of people carrying tuberculosis; health care workers; veterinary and other workers who handle animals susceptible to tuberculosis; staff working in prisons, in residential homes and in hostels for refugees and the homeless; and people intending to stay for more than one month in countries with a high incidence of tuberculosis.

A skin test may be performed before the vaccine is given to check that you don't already have antibodies to the tuberculosis bacteria, either from a previous vaccination or from previous exposure to the disease. This test uses tuberculin PPD and is called the Mantoux test. For more information see the tuberculin PPD factsheet.

For children up to six years of age, the Mantoux test is not required before the vaccine is given, providing that the child has not lived or stayed for more than one month in a country with an annual TB incidence of 40 per 100,000 people or greater and they have not had contact with a person with known tuberculosis. All other people should have the Mantoux test before vaccination.

What is it used for?

Prevention of tuberculosis

Warning!

The BCG vaccine usually causes a hardened lesion that may ulcerate and occasionally discharge. It heals over several weeks or months leaving a small flat scar. You should keep the area dry to allow it to heal, but it is not necessary to protect it from water during washing or bathing. Avoid covering it with waterproof (airtight) dressings or tight clothing, unless for short periods such as during swimming. If the ulcer starts to ooze you can cover it with a dry dressing until a scab forms, but you should still allow the air to get to it. Airtight dressings may delay the healing of the ulcer and cause a larger scar. If you get a more severe reaction or the ulcer persists seek medical advice from your doctor.

Use with caution in

Eczema (skin at injection site should be free from eczema)

Not to be used in

Fever (pyrexia)

Generalised infected skin conditions

People who have had tuberculosis

People with positive skin reaction to tuberculin (Mantoux test)

Newborn children in a household where an active TB case is suspected or confirmed

HIV infection

Infants born to HIV positive mothers

Malignant conditions such as leukaemia and lymphoma

People who are or who have recently received treatment that suppresses the activity of the immune system, eg long-term oral corticosteroids, chemotherapy, radiotherapy, medicines to prevent transplant rejection

People who are receiving preventative anti-tuberculous medicines

People with decreased defences against disease or infection (impaired immune response) due to disease or treatment

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

This vaccine should not be given during pregnancy or breastfeeding unless considered essential by your doctor. Seek medical advice.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Headache

Fever (pyrexia)

Hardening of skin at injection site, followed by a lesion that may ulcerate and heal over some months, leaving a small flat scar

Swelling of the lymph nodes near the injection site

Occasionally, an excessive response to the vaccine resulting in a discharging ulcer

The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

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