If you’ve ever had chicken pox, you could get shingles at any time. The painful rash is caused by the same virus, which can remain dormant in the body for decades. What’s more, once the rash disappears, extreme pain in the affected area can persist for weeks, months or even years. Scientists don’t know exactly why shingles emerges, though it’s often associated with a weakened immune system or stress.

Healthy people over age 60 can greatly reduce their shingles risk with a one-time vaccine, even if they’ve had shingles in the past. The shingles vaccine has been around since 2006, is widely viewed as safe and free from major side effects, and doctors generally endorse it. All that hasn’t translated into widespread use, though.

For one thing, the manufacturer initially couldn’t produce enough vaccine to guarantee a steady supply. Also, the vaccine must be kept frozen until just before use, which makes it difficult for doctors’ offices to store. And, it’s expensive. One shot might cost a patient more than $100 … and some insurance companies require patients to pay first and then seek reimbursement. But many pharmacies are now offering the vaccine — and some are marketing it heavily. In some states, after a quick screening a patient can receive the vaccine right at the pharmacy — without a doctor’s prescription. If supply remains ample, some observers say pharmacies could be the vital link in making this vaccine a public health success story.

Shingles affects about 1 million people in the United States each year. The Centers for Disease Control and Preventiom has not officially recommended it for people ages 50 to 59, but research has demonstrated its effectiveness in that age group, too. If the shot catches on, a generation of chicken pox survivors may be spared the unpleasantness of shingles.