Bacille Calmette-Guerin (BCG) Vaccine
Tuberculosis is caused by mycobacteria. It spreads through the air and usually affects the lungs (pulmonary TB). Other parts of the body, such as bones, liver, brain and kidneys, can also be affected (extrapulmonary TB). TB is still an important infectious disease locally, since Hong Kong is a densely populated community.
A. Why get vaccinated?
Although BCG does not offer 100% protection against TB, it helps to localize infection to the lungs and is effective in protecting against serious complications of the disease. In Hong Kong, BCG vaccine is included in the Hong Kong Childhood Immunisation Programme.
B. When should my child get vaccinated?
All local newborns should be given BCG at birth. For children aged less than 15 years, residing in Hong Kong and not given BCG before, direct BCG vaccination is recommended.
C. The following individuals should NOT receive BCG
- has received other live vaccines in the past four weeks (BCG can be given after this interval)
- under immunosuppressive therapy (e.g. irradiation, treatment with cytotoxic drugs or systemic steroids)
- immunodeficiency, either congenital or acquired (e.g. HIV infection)
- cancer (e.g. leukaemia, lymphoma)
- severe skin diseases
- babies of mothers who received biological therapy during pregnancy (consult specialists as deferral of vaccination is likely)
D. What are the side effects?
- Some children may develop a small red papule or ulcer at the site of injection 2 to 4 weeks after vaccination. This will gradually subside and heal in a few weeks, leaving a small scar or no scar at all. Occasionally a few children may develop lumps under the armpit due to enlarged glands. Other adverse reactions are very rare.
- Parents do not have to worry if there is pus or ulceration. This is a normal reaction. The child can take baths as usual. Keep the injection site clean and dry. Use cooled boiled water for cleaning the site if necessary, and wipe dry with a clean gauze afterwards.
- Do not apply any medication or ointment and do not compress or bandage the site. Wear loose clothing.
- Most localised complications of BCG vaccination will self-resolve, therefore parents do not need to worry.