Q: Hello Dr, is there any problem if one was given a BCG vaccine and the scar is not there. I am 25 yrs old.

A: The full meaning of BCG is Bacille Calmette-Guerin, named after scientists, Drs Calmette and Guerin who developed the vaccines. It was used for the first time in human beings in 1921. This is a freeze-dried live but weakened strain of Mycobacterium Bovis (very similar to the bacteria that cause tuberculosis), a bacterium found in cattles which can cause tuberculosis in man. This vaccine is part of the compulsory immunization schedule in countries with a high incidence of tuberculosis. It provides protection over a a range of 10-20 years and so is not particularly useful in adults…sorry 😉

This vaccine usually causes a local reaction in most, but not all people. This local reaction gives rise to the ‘infamous’ scar 😀 but does not really act as a marker for protection against tuberculosis. So, if you don’t have a BCG scar, it does not mean that you did not respond to the vaccine and there’s certainly no need for you to take another dose of the vaccine.

Have a good night, y’all 😀