[Noah930]

I think it's pretty low. As in, it would be unusual for you to come down with Chicken Pox/Shingles, if you were truly exposed to it as a kid. People who have Shingles usually have it because of some sort of weakness in their immune system. Not necessarily in the HIV/AIDS or cancer chemotherapy immune system weakness, but even things like excessive stress/anxiety/fatigue/etc. Then, the Varicella virus that has been hiding, dormant in your neurological system, then seizes the opportunity to flare up in the characteristic dermatomal distribution.

You can check a titer level (via bloodtest) to see if you've been adequately exposed to Varicella in the past. If you find that your titer level is too low, there's a vaccine (think it's a series of 3 injections) available. Then you check your titer level again, to make sure you've developed adequate resistance. If not, go through the vaccinations again.