BCG

Bacille Calmette-Guérin (BCG) - What it is

BCG, or Bacille Calmette-Guérin, is a vaccine given to prevent tuberculosis (TB), especially in infants and children. It reduces the risk of developing all forms of TB by 50% and deadly forms of TB by up to 80%. The risk of long-term disability and death is high in children who are infected with TB.

BCG is given to all children around the world where TB is common. Although there has been a large reduction in TB rates in Singapore since the 1950s, it is still common. Globally, a third of the world’s population is estimated to be infected with TB.

The BCG vaccine contains a weakened form of live bacteria related to TB. The administration of the vaccine makes the body’s immune system produce antibodies to fight TB. The administration is in levels that do not cause the disease.

Bacille Calmette-Guérin (BCG) - Treatments

When and what happens when BCG is given?

In Singapore, BCG is usually given to babies soon after birth.
A weal (or raised red mark on the skin) appears after the injection and disappears within half an hour.
After two to three weeks, a small red, firm nodule appears and slowly increases in size for about a week. It becomes filled with pus-like material, before bursting and forming a shallow ulcer. This may not even be noticeable to parents.

For most children, the ulcer heals on its own. There is NO NEED to apply elastoplast, ointment or powder on it. Sterile gauze can be applied if there is a lot of pus discharge. The gauze should be light and allow fluids to pass through easily. By the 12th week, healing is usually complete and a small permanent scar may be left as evidence of BCG vaccination.

Bacille Calmette-Guérin (BCG) - Other Information

What must I take note of?

In rare circumstances, however, BCG vaccination can lead to complications. In approximately one in 1,000 babies, it leads to the development of either:

a persistent abscess or pus collection over the BCG site beyond the 12th week, or
an enlarged lymph node (which feels like a small fleshy lump) in the armpit (if the BCG vaccination was at the arm) or groin (if the vaccination was at the buttocks) that may become pus-filled or even discharge pus.

If the above occurs, you should take the baby to a doctor for further medical advice. The most severe form is widespread or “disseminated” BCG which occurs in around one out of 100,000 children who have an underlying defect in their immune systems (the body’s defence against infections). These children often have an ulcer that does not heal and/or lymph node enlargement together with enlargement of the liver and spleen. These children should be brought to specialist centres such as KK Women’s and Children’s Hospital (KKH), for further medical care.

BCG vaccination has more benefits than risks. Besides protecting your child with BCG vaccination, adults should also take precaution against TB with routine care. We hope that TB in Singapore will become less common in future so that it may not be needed anymore.