My child has been offered a BCG vaccine, but I have heard it is dangerous?

The safety of vaccines is considered very carefully.  When vaccines are offered it is because the risk of not having them (i.e. the risk of harm from a disease or illness) is considered significantly higher than the risk of harm from the vaccine.  In the UK only children who are at higher risk of catching TB are offered the vaccine. 

No medical intervention, including vaccines, is guaranteed 100% safe for everyone. There can be side effects to the BCG, ranging from abscesses at the site of the injection, to swelling in the lymph nodes.  Very rarely indeed, the vaccination can cause BCG disease, which can be fatal. This is most likely to happen in people with damaged immune systems and for this reason the vaccine should not be given to anyone who is HIV positive.