Washington - An experimental vaccine reduces the risk of developing a painful skin disease known as shingles by half, a study published on Thursday found.
And in those people who still develop the shingles, the vaccine cuts by two-thirds the chances that the patient will suffer from chronic pain after the outbreak, according to the study by American researchers in the New England Journal of Medicine.
Shingles is caused by the same virus that causes chickenpox. After a person has the chickenpox, the virus lies dormant in the nerve cells of the body.
Shingles develops when that virus reawakens, forming a rash on one side of the body, usually on the chest, back or face, that is more painful than itchy. Sometimes the pain is so intense, sufferers have problems wearing clothes.
The disease strikes the old most often because of their declining immunity.
The study tested the vaccine in more than 38 500 men and women at hospitals operated by the US Department of Veterans Affairs. Some got the vaccine - a live but weakened strain of the Varicella-zoster virus, which causes shingles - and the rest got a placebo.
The study group was followed for an average of three years and evaluated for shingles. In the placebo group, 3,3 percent developed shingles while 1,6 percent did in the vaccine group.
The researchers - led by Michael Oxman, an infectious diseases specialist at the VA San Diego Healthcare System in California - found that the vaccine was more effective in preventing shingles in younger people but it was better at preventing long-term pain in the older subjects.
Of those you developed shingles in the vaccine group, the rate of chronic pain was reduced 66 per cent, according to the study, which was run by the Veteran Affairs Department, the National Institutes of Health and the vaccine's maker, Merck and Company.
Merck has asked the US government's watchdog, the Food and Drug Administration (FDA), to approve the vaccine. The approval would be beneficial to the US drugmaker, who received a blow with the recent withdrawal of its painkiller Vioxx.
The FDA was expected to decide on the drug early next year.
There were no major complications from the vaccine. - Sapa-dpa