About one out of three Americans will develop shingles, which is caused by the same virus that triggers chickenpox. Although anyone who’s had chickenpox is at risk for shingles at any point in their life, about half of all cases involve people 60 or older, according to the Centers for Disease Control and Prevention. The main symptom is a painful rash that develops on one side of the face or body, with blisters that scab over in about a week. The only way to reduce the risk is to get vaccinated, so the CDC recommends people 60 and older get the shingles vaccine regardless of whether or not they recall having had chickenpox.

Shingles occurs when the virus that causes chickenpox starts up again in your body. After you get better from chickenpox, the virus “sleeps” (is dormant) in your nerve roots. In some people, it stays dormant forever. In others, the virus “wakes up” when disease, stress, or aging weakens the immune system. Some medicines may trigger the virus to wake up and cause a shingles rash. It is not clear why this happens. But after the virus becomes active again, it can only cause shingles, not chickenpox. You can’t catch shingles from someone else who has shingles. But there is a small chance that a person with a shingles rash can spread the virus to another person who hasn’t had chickenpox and who hasn’t gotten the chickenpox vaccine.

The rash caused by shingles is more painful than itchy. The nerve roots that supply sensation to your skin run in pathways on each side of your body. When the virus becomes reactivated, it travels up the nerve roots to the area of skin supplied by those specific nerve roots. This is why the rash can wrap around either the left or right side of your body, usually from the middle of your back toward your chest. It can also appear on your face around one eye. It is possible to have more than one area of rash on you.

As soon as you are diagnosed with shingles, your doctor probably will start treatment with antiviral medicines. If you begin medicines within the first 3 days of seeing the shingles rash you have a lower chance of having later problems, such as postherpetic neuralgia. There’s new evidence shingles may come with health consequences beyond an agonizingly painful rash: It could mess with your heart health, too. The new study could offer more motivation to get the shot.

It’s important that doctors treating patients with shingles make them aware of their increased heart disease risk, But the findings will not change current U.S. recommendations — there’s no additional action to be taken by a patient. The basic advice to lower your heart attack and stroke risk remains the same: Don’t smoke, exercise 30 minutes most days and know what your cholesterol level is. Maintain a normal body weight, be screened for diabetes and have it under control; know your blood pressure and if it’s high and talk to your doctor about treatment.