Nov. 2, 2009 (Philadelphia) -- People with shingles are more likely to suffer a recurrence than previously thought, especially if their attack is accompanied by lasting pain, researchers report.
"The risk of getting shingles again, once you already have it, is about one in three," says Barbara Yawn, MD, director of research at Olmsted Medical Center in Rochester, Minn. "That's about the same chance of getting shingles once in your lifetime."
People who suffer pain for 60 or more days after their shingles attack are nearly five times more likely to suffer a recurrence, Moore says.
The research was presented at the annual meeting of the Infectious Diseases Society of America (IDSA).
Also known as herpes zoster, shingles is caused by the varicella-zoster virus (VZV) -- the same virus that causes chickenpox.
In many people, the virus remains dormant in the nerves. But in some, especially older people and those with compromised immune systems, it can reactivate as shingles.
"We don't know what causes reactivation of the dormant virus," Moore says.
The reawakened virus initially causes numbness, itching, severe pain, and even fever, headaches, and chills, followed by the blistering rash characteristic of shingles. The skin rash usually occurs within three to five days after symptoms begin.
Shingles can result in persistent pain lasting for months and even years after the rash has gone away.
"But unless someone has a compromised immune system, we didn't think they would actually have a recurrent attack," Moore says.
Risk Factors for Shingles Recurrence
Moore and colleagues studied the medical records of nearly 1,700 people with a confirmed shingles attack from 1996 to 2001. Only 8% had compromised immune systems, she says. But 95 of them suffered 105 recurrences by the end of 2007.
"Clearly most recurrent attacks are occurring in people with healthy immune systems," she says.
The time between attacks ranged from 96 days to 10 years.
- 2.8 times more likely in people with shingles-associated pain for 30 or more days during the initial episode
- 4.8 times more likely in people with shingles-associated pain for 60 or more days during the initial episode
- 60% more likely in women than men
- 40% more likely in people who were 50 or older when they had their initial attack
"Still, most recurrences occurred in people with none of these risk factors," Moore says.
The only way to protect yourself against shingles is to be vaccinated, she adds. The vaccine, known as Zostavax, was approved for use in adults ages 60 and older after studies showed it prevents shingles about half the time.
IDSA spokesman Aaron Glatt, MD, of the New Island Hospital in Bethpage, N.Y., tells WebMD that he was "surprised" at the high rate of recurrence.
"We knew you could get another episode, but we didn't know the risk was so great," he says.
Merck, the company that makes the vaccine, funded the study.