Misconception 3: “If you don’t have the scar, you weren’t vaccinated”
People often compare arms with friends or family and assume that the presence—or absence—of the scar proves whether someone was vaccinated.
The truth:
Not everyone who receives the BCG vaccine develops a visible scar. Some people heal with little or no mark at all, while in others the scar fades significantly over time.
The absence of a scar does not automatically mean a person was never vaccinated—just as having a scar doesn’t mean stronger or weaker immunity.
Misconception 4: “The scar means your immune system is weak or damaged”
Another common 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. The body recognizes the weakened bacteria in the vaccine and mounts a localized response, which can leave a small mark.
