After you get chicken pox, the virus continues to live in your body but is dormant (inactive), meaning that it does not cause symptoms. It is estimated that 99% of adults over age 40 years have had chicken pox and are at risk for shingles.
Shingles occurs when the virus is reactivated. This can occur when your body is stressed or your immune system is weakened. Immunosuppression can happen when you are being treated for cancer, have HIV, had an organ transplant, or are on immunosuppressive therapies (including chronic steroids) for conditions like inflammatory bowel disease, rheumatoid arthritis, or psoriasis. Please know that this is not an all-inclusive list.
It is also important to realize that you can get shingles when you are healthy. That’s because the immune system gradually weakens as you get older. The rate for shingles increases significantly after the age of 50. One study even showed that postherpetic neuralgia was 15 times more common in people 50 years or older when compared to those who were younger.