Adverse events following BCG immunization and how to treat them

Adverse events may occasionally occur after immunization, in addition to the desired protective effect. They can include swelling and tenderness at the injection site. For BCG immunization, the normal reaction is a small raised swelling, which immediately appears at the injection site. This usually disappears within 30 minutes.

A small raised swelling can be seen at the site of an intradermal BCG injection. (Photo: AMREF Ethiopia/Demissew Bizuwork)

After approximately two weeks, a small red sore normally develops at the injection site, which is about 10 mm in diameter (the size of the unsharpened end of a pencil). The sore remains for about another two weeks and then heals, leaving a small scar about 5 mm across. This is a sign that the child has been effectively immunized. If there is no scar at the injection site six weeks after a BCG immunization, the injection must be repeated. If there is still no skin reaction to the second injection, the child should be referred to a higher-level health facility.

(a) The small sore at the injection site is a sign that the child has been effectively immunized with BCG vaccine. (b) A healed BCG vaccination scar on the arm of an adult. (Photos: supplied by Dr Kalid Asrat and Dr Basiro Davey)

Occasionally, there is an abnormal adverse event following BCG immunization, such as swelling of glands in the armpit, or rarely the formation of an abscess at the injection site.

An abscess is a collection of pus and inflamed tissue at the site of bacterial infection. It can be due to bacterial causes other than BCG.

An abscess is a rare adverse event following BCG immunization. This one is about 1.5 cm in diameter, but they can be larger. (Photo: supplied by Dr Kalid Asrat)

Abnormal adverse events following BCG vaccination may occur because:

  • an unsterile needle or syringe was used
  • too much vaccine was injected
  • the vaccine was injected too deeply under the skin, instead of into its top layer.

Adverse events following BCG immunization and their management.

Adverse eventsManagementComments
Small sore at the site of injection after two weeks, which may last two weeks Keep dry and clean (do not put any ointment on the sore or give the child any medicine) Will heal naturally to leave a small scar
Swollen glands (lymph nodes) in the armpit Surgical or drug treatment may occasionally be required at a higher health facility Refer the child to a higher health facility
Abscess at the injection site

Amoxicillin syrup is an antibiotic preparation used to treat bacterial infections, which is available at rural health facility level. daily

Amoxicillin syrup orally three times

Refer the child urgently to the next higher health facility
Last modified: Saturday, 12 July 2014, 2:40 PM