Shingles is caused by the varicella zoster virus, the same virus that causes chickenpox. After a person recovers from chickenpox, the virus stays in the body in a dormant (inactive) state. For reasons that are not fully known, the virus can reactivate years later, causing shingles. Almost 1 out of every 3 people in the United States will develop shingles, also known as zoster or herpes zoster. There are an estimated 1 million cases each year in this country. Anyone who has recovered from chickenpox may develop shingles; even children can get shingles. However 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.