New York, Feb 12 (IANS): Shingles, a viral infection caused by the chickenpox virus, is linked to an increased risk of stroke, but researchers have recently found that Zoster Vaccine Live, one type of shingles vaccination, may prevent some older adults from having a stroke.

Shingles is a reactivation of the chickenpox virus and typically occurs after age 50. The risk of developing shingles, a painful condition that causes skin blisters and can have serious complications, increases with age and other health conditions.

"One in three people who have had chickenpox develop shingles in their lifetime. The Zoster Vaccine Live helps to prevent shingles and reduces the risk for shingles by about 51 per cent," said study lead author Quanhe Yang from the Centres for Disease Control and Prevention (CDC) in the US.

To help determine if the shingles vaccine reduces the risk of stroke, the researchers reviewed the Medicare health records of more than one million Medicare fee-for-service beneficiaries age 66 or older who had no history of stroke and who were administered the Zoster Vaccine Live between 2008 and 2014.

They followed them for an average of almost four years.

That group was matched with the same number of Medicare fee-for-service beneficiaries who did not receive the shingles vaccine with the same four-year follow-up.

To examine the effect of the vaccine on risk of stroke, researchers controlled for age, gender, race, medications and co-existing health conditions.

Researchers found the receiving the shingles vaccine lowered the risk of stroke by about 16 per cent, lowered the risk of ischemic (clot-caused) stroke by about 18 per cent and lowered the risk of hemorrhagic (bleeding) stroke by about 12 per cent.

The vaccine's protection was strongest among people ages 66 to 79 years; and among those under the age of 80 years, the shingles vaccine reduced the risk of stroke by nearly 20 per cent and in those older than 80, reduced the risk by about 10 per cent.

"The reason for increased risk of stroke after a shingles infection may be due to inflammation caused by the virus," Yang said.

The study is scheduled to be presented at the American Stroke Association's International Stroke Conference slated from February 19 to 21 in the US.