Question

The child is three months old and received the BCG vaccine on September 27th. Recently, a swelling was found at the injection site, inquiring whether this is an adverse reaction to the vaccine and the possible time frame for such reactions.

Answer

Based on the description and the photos provided, the situation appears to be a normal response to the BCG vaccination, and there is no need to worry. BCG inflammation is a common vaccination reaction, usually resulting in a slight inflammatory reaction at the injection site, which indicates successful vaccination. If there is no inflammatory reaction, it may be necessary to administer the vaccine again. After successful vaccination, a scar typically forms.