Why do people develop shingles?
Shingles develops if the virus that is still in your body after having chickenpox is reactivated. Most of us get chickenpox in childhood. It is rarely a serious illness and usually clears up on its own within a week or two. However, once you have had chickenpox, the virus remains dormant in your nerve roots for the rest of your life.
The virus is held in check by your immune system, and most of us never notice it again. With advancing age, however, the immune system deteriorates and is not always capable of controlling the virus, which then can become reactivated and migrate along a nerve to the skin. There it causes fluid-filled, itchy, and often painful blisters – shingles. Read more about the symptoms of shingles here.
Shingles is NOT caused by a new infection or contact with the virus through someone who has shingles. It is your own existing infection leaping back into life.
Hence, you can’t get shingles from someone who has chickenpox. If you have shingles, however, you can infect people who have not previously had chickenpox. If so, they then develop chickenpox, not shingles.