Many cases of shingles may be prevented with an experimental vaccine that could be on the market as early as next spring, medical experts said yesterday.
The disorder, typified in many cases by excruciating pain, itching and throbbing, is caused by a resurgence of the chicken pox virus, usually after age 60.
Varicella zoster, the microbe that causes both shingles and chicken pox, retreats after a childhood bout with the itchy and blistering condition, only to resurface decades later as shingles, a nerve-damaging disorder that sometimes is so painful that people have considered suicide. Varicella zoster is a member of the herpes family.
"This is a landmark study and the largest vaccine study in the world," said Dr. Shing-shing Yeh, a physician and researcher at the Northport Veterans Affairs Medical Center on Long Island.
Doctors from 22 VA medical centers nationwide participated in the trial, which included more than 38,000 participants whose average age was 69.
However, shingles has been known to occur in children as young as 3, said Dr. Stephen Straus, a senior scientist at the National Institute of Allergy and Infectious Diseases. But shingles pain becomes far more intense with age.
Strauss said doctors can tell the difference between the eruptions of chicken pox and shingles by how the rashes appear.
In chicken pox, the virus is carried by the bloodstream, prompting rashes and blistering all over the body. In shingles, the eruptions follow the path of the damaged nerve.
Straus said it is important to seek treatment. When the eruptions are on the face, the virus can spread to the eyes and cause blindness.
Writing in today's New England Journal of Medicine, researchers reported that the experimental vaccine, a product of Merck Corp., reduced the incidence of shingles by 51 percent.
A second, more debilitating shingles-related condition, post-herpetic neuralgia, which is pain radiating from severely damaged nerves, was reduced by 66 percent, Yeh said.
During the trial, patients received either the vaccine or a placebo. In the placebo group, 642 cases of shingles were diagnosed but only 315 were diagnosed among vaccinated patients. The vaccine is a version of the live-virus chicken pox vaccine that has been administered to children since 1995.
Christine Fanelli, a spokeswoman for Merck Vaccines, said the company is seeking Food and Drug Administration approval of the shingles shot.
While shingles responds readily in some patients to treatment with acyclovir, an antiviral drug, it can prove difficult to treat in many others. The disorder is considered a major public health concern, affecting an estimated 600,000 to 1 million people annually, according government health statistics.
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