What caused the smallpox vaccine to leave a mark?

The smallpox vaccine induced scars due to the body’s recuperative processes. The vaccine itself was administered quite differently from many contemporary vaccines, using a specialized double-pronged needle.

The individual administering the vaccine made multiple punctures in the skin (rather than the single injection typically given with today’s vaccines) to deliver the vaccine to the dermis of the skin (the layer below the epidermis).

The viral content within the vaccine then began to replicate, leading to the formation of round bumps. These bumps subsequently evolved into vesicles (small, fluid-filled blisters), which would eventually rupture and scab over with time.

The outcome is the notorious scar we have discussed in this piece.

Do you possess a scar from the smallpox vaccine? Share with us in the comments!