TB and BCG Vaccine

What is BCG?

BCG (Bacille Calmette-Guerin) vaccination gives protection against the disease Tuberculosis. Tuberculosis (TB) It is one of the leading causes of death from infectious disease in the world. One third of the world’s population are infected with TB and nearly two third of those people live in Asia. Of those infected only a small proportion will become ill.

Infants and the elderly are particularly at risk. Most infections are confined to the lung, however infants are more prone to rapid and widespread illness (e.g. meningitis – where the infection spreads to the lining of the brain). TB is spread through close contact with infected individuals. Usually people acquire the disease from household contacts or if in constant contact with high-risk populations.

The BCG vaccination does not prevent TB. It decreases the likelihood of severe illness, spread beyond the lungs, and death in young children.


There is a great range of recommendations for vaccination from various health authorities around the world. The CDC in the USA for example does not recommend BCG for travelers unless they are children and have the potential to be continuously exposed to high-risk groups/populations.

The World Health Organization, Australia, UK and The Netherlands recommend vaccination for those 5 years or younger (long stay). BCG has a less certain role for those over 5 years old and this should be discussed with your doctor.
The Singapore immunization authority recommends BCG vaccination at birth.

The Vaccine

If your child is more than 6 months old a Mantoux test is necessary prior to the BCG vaccination. This is done to make sure there has been no previous contact with TB. The Mantoux test is done on the forearm and is read by the doctor at 48-72 hours. If the test is negative then the BCG is given. The BCG is given in the left upper arm as an injection just below the surface of the skin. The site and depth of the vaccine are important to minimize chances of side effects of the vaccination. It can also be given in the gluteal region.

The normal response to the BCG vaccination initially is a small red raised area, which forms an open sore and usually takes several weeks to heal. Abscesses and larger local reactions can occur. These can take several months to heal. A permanent scar can be expected from a BCG vaccine.

Caring for the BCG sore

In general the sore created by the vaccination should be left alone. Within 2-6 weeks of injection, a small lump may develop at the site of the vaccination. This will slowly increase in size (often up to 1cm in diameter) and may have a flaky, scaly or bruised appearance. This is normal. Occasionally a blister and then a small ulcer will develop. This may “weep” a little.

It is not necessary to protect the site from becoming wet during washing and bathing. However, should any oozing occur, a temporary dry dressing may be used until a scab forms. It is essential that the area be allowed to “breathe”. Air must reach the area otherwise healing will be delayed and a larger scar may develop.

It takes several months for the swelling to subside completely. You may be left with a small flare scar at the site of the injection. This is permanent. The scar is usually much smaller than the area of initial swelling. Occasionally the glands in the armpits / groin may become swollen and tender after the BCG vaccination. This is a normal reaction.

If you are worried about anything related to the vaccination and are concerned about what you see, please contact the clinic.

BCG and other vaccinations

No further vaccinations should be given in the arm used for BCG for 3 months to decrease the chance of local lymph node inflammation. A month’s interval is required if administering another “live” vaccine if not administered on the same day.

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