Q: Shots hurt. Why do I need to get a vaccine through a shot? Why can't I just rub the vaccine on my skin?
A: In order for the vaccine to work, it must enter your bloodstream so that it can spread throughout the body. However, one of the body's first lines of defense is the skin, which is composed of the epidermis (the thin outer layer) and the dermis (the thicker inner layer). The skin acts as a barrier to prevent the entry of pathogens. Unfortunately, the skin also prevents vaccines from entering your body. So, in order to inject the vaccine into your bloodstream, a shot is required to puncture your skin.
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