Side effects of BCG vaccination
NHS Choices Medical Reference
Around 90-95% of people will develop a raised blister at the site of the injection immediately after the vaccination. This is normal, and nothing to worry about.
Two to six weeks after the injection, a small spot may appear at the site of the injection. This can be painful for a few days, but should settle. The spot will eventually heal, but it may leave a small scar.
Rarely, some people may have a more severe skin reaction. This should heal within a few weeks.
If you are worried that your skin reaction is abnormal or that the spot may have become infected, contact your GP or telephone NHS Direct on 0845 4647.
Serious side effects, such as an anaphylactic reaction (a serious allergic reaction), are very rare. They occur in less than one in a million cases.