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 (Figure 2.2 on the next page). This usually disappears within 30 minutes.

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 (Figure 2.3). 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.

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 (Figure 2.4).

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.

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.

Table 2.2 summarises the adverse events that may occur following BCG immunization and how you can treat them at Health Post level.

Table 2.2  Adverse events following BCG immunization and their management.