MODEL RELEASED. BCG vaccination scar on the arm of a seven-month-old baby boy. This blister or papule forms after injection, into the skin, of the vaccine that protects against tuberculosis (TB). Most children receive the vaccine at around the age of 13. However, in cases where the risk is considered high, babies are given the vaccine soon after birth. The papule heals after 10 to 12 weeks leaving a small scar. BCG (bacille Calmette- Guerin) is named after the two French scientists who developed the vaccine in 1906.