By Will Dunham

WASHINGTON (Reuters) - U.S. health officials on Thursday recommended that people 60 and older get Merck & Co Inc's (MRK.N: Quote, Profile, Research) vaccine Zostavax to protect against shingles, a viral infection that causes a painful, blistering rash.

The risk of getting shingles -- caused by the same varicella-zoster virus responsible for the common childhood illness chicken pox -- rises with age starting at around age 50, and is highest among the elderly.

The U.S. Centers for Disease Control and Prevention said it is recommending a single dose of Zostavax, the only vaccine to prevent shingles, for people age 60 and older, even if they have had a prior episode of shingles.

The agency said the recommendation replaces a provisional one it made in 2006 after the vaccine was approved by the U.S. Food and Drug Administration and recommended by a CDC advisory panel of immunization experts.

The CDC said researchers have found the vaccine cuts the occurrence of shingles by about 50 percent in people age 60 and older. For people ages 60 to 69, it cuts the occurrence of the disease by 64 percent, the CDC said.

About a third of all people in the United States will get shingles, including half who reach age 85, the CDC said.

There is no cure for shingles, also known as herpes zoster. After a person has had chicken pox, the virus remains dormant in the body, and years later can reactivate as shingles.

"It is a nasty, life-altering affliction. Although the vaccine is not perfect, it's pretty good," Dr. William Schaffner of Vanderbilt University Medical Center in Nashville, Tennessee, vice president of the National Foundation for Infectious Diseases, said in a telephone interview.