ANSWER: Shingles is caused by the varicella-zoster virus, the same virus that causes chickenpox. Once you've had chickenpox, varicella-zoster stays in your body for the rest of your life. When the virus is reactivated, the result is shingles.
Shingles typically involves a band-like rash on one side of the chest, abdomen or face. The rash is usually quite painful. Most people recover from shingles over several weeks. A small number have lingering severe pain, called post-herpetic neuralgia, along the nerve that was irritated when the virus came back.
Shingles often occurs when a person's immune system is impaired. A weakened immune system can be part of the aging process. That's why shingles tends to be more common in people older than 50. The risk of shingles continues to increase as people age. Some experts estimate that half the people who live to age 85 will get shingles at some point.
Shingles can affect younger people, too, as a result of factors that can affect the immune system. Periods of high stress, depression and prolonged fatigue may weaken the immune system in otherwise healthy young adults and lead to shingles. Chronic illnesses such as chronic kidney or lung disease, cancer, HIV/AIDS or other diseases that affect the immune system also may increase the risk of a shingles eruption, regardless of age.
Certain medications -- such as steroids or immunosuppressive medications used to treat autoimmune diseases or to prevent rejection of transplanted organs -- weaken the immune system, as do some types of medical treatment, such as chemotherapy. These also can make a person more vulnerable to shingles.
The fact that you had shingles at your age does not necessarily mean you're at high risk for developing the illness again. In general, only about one to four percent of people who have shingles once go on to have a recurrence. That percentage is higher in people who have chronic diseases that affect their immune systems or who are on long-term drugs to suppress the immune system.
The shingles vaccine can help prevent the disorder and lower the likelihood of complications, such as lingering pain. The U.S Centers for Disease Control and Prevention recommends that all adults age 60 and older who have had chickenpox get the shingles vaccine, even if they've already had shingles. Studies also have shown the vaccine to be effective in patients between 50 and 59 years of age. Because it has not been studied in younger people, it's not clear how effective the vaccine is for healthy adults younger than 50 in lowering the risk of recurrent shingles.
The vaccine is made from a weakened form of the live shingles virus, but it does not cause the illness in healthy people. For those with chronic diseases or who are on chronic medications that weaken the immune system, the vaccine is not an option due to a risk that it may cause shingles in those groups.
At your age, whether or not you get the vaccine is an individual decision that should be based on your medical history and what, if any, other health conditions you may have. Talk with your health care provider to see if the shingles vaccine is a good choice for you at this time.
-- James Watson, M.D., Neurology, Mayo Clinic, Rochester, Minn.
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