BCG vaccine scar. Scar on the arm of a 13-year-old boy following vaccination with BCG to protect against tuberculosis (TB). BCG (bacille Calmette- Guerin) is an artificially weakened form of the bacterium that causes bovine (cattle) TB. A pre- vaccination tuberculin test is carried out to ascertain the immune status of the individual. If negative they are vaccinated. Here, the injection site two months after vaccination is shown. A local reaction has occurred at the site causing redness and a small ulcer (at centre). This heals after about two months leaving a small scar.






























