Commonly known as shingles, herpes zoster is a viral disease characterized by a painful skin rash with blisters in a stripe pattern on either the left or right side of the body. The initial infection with varicella zoster virus (VZV) causes the acute and short-lived illness chickenpox which generally occurs in children and young adults. Once an episode of chickenpox has resolved, the virus is not eliminated from the body but can go on to cause shingles often many years after the initial infection. About 1 out of every 3 people in the world develop shingles. The risk of disease increases as a person gets older. About half of all cases occur among men and women 60 years old or older.