Originally Posted by
roccobike
Actually, vaccines don't stop you from "getting" any virus. They simply help your immune system to recognize and overcome the disease before it goes viral.
In the case of shingles, you already have the virus from prior exposure to chicken pox; it's just been suppressed by your immune system. If/when your immune system weakens, as happens when we age, or come under stress, the dormant virus can become active and present as shingles. The vaccine bolsters the specific aspects of your immune system that suppress the Herpes zoster virus, and in that manner prevents shingles from developing.