BCG Vaccination - Reaction and Care

  • BCG(Bacile Calmette-Guerin) 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 Immunization Programme.

  • 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. 

Below shows the normal localized reaction after BCG vaccination:


  • The following points should be noted after BCG vaccination:
  1. Parents do not have to worry if there is pus or ulceration. This is a normal reaction.
  2. 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.
  3. Do not apply any medication or ointment and do not compress or bandage the site. Wear loose clothing.
  4. Most localised complications of BCG vaccination will self-resolve, therefore parents do not need to worry.

The information is provided by Family Health Service, Department of Health

Version 2.0   Effective date: 6.2020


Photos are for reference only.