Shingles arises because the varicella zoster virus (VZV, which causes chickenpox) can remain dormant in nerve cells after chickenpox has subsided. Re-activation of VZV, for reasons which are poorly understood, leads to shingles.

A live vaccine for VZV is available. A Cochrane meta-analysis, which looked eight RCTs with 52269 subjects showed that the vaccine reduces the risk of shingles by about 50% with minor adverse effects; http://onlinelibrary.wiley.com/doi/1...D71BB3D.f04t03 .