Misconception 4: “The scar means your immune system is weak or damaged”

Another fear is that the scar signals long-term harm to the immune system or ongoing vulnerability to illness.

The truth:

The BCG scar is not a sign of immune weakness. In fact, it represents a normal immune reaction to the vaccine. The body recognizes the weakened bacteria in the vaccine and mounts a localized response, which can leave a small mark.

In many cases, the vaccine has been associated with positive immune training, especially in early life. The scar itself has no negative effect on health.

Misconception 5: “It’s dangerous or something that should be removed”

Some people feel self-conscious about the scar and worry it might be unsafe, abnormal, or something that needs medical treatment.

The truth:

The BCG scar is harmless. It does not grow, spread, or turn into a medical problem. There is no medical reason to remove it unless someone chooses to do so for cosmetic reasons.

Doctors generally consider it a normal, benign mark—nothing more than a quiet reminder of early protection.