FWD:Vaccine curbs shingles

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From: byrd45 (Original Message) Sent: 6/2/2005 9:56 AM
Vaccine Curbs Shingles Cases and Severity
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Published: June 2, 2005
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An experimental vaccine can reduce both the incidence and the severity of shingles by more than half, doctors reported yesterday, in a development that could spare hundreds of thousands of elderly Americans from an extremely painful disease.

The effectiveness of the vaccine was determined in an unusually large clinical trial involving more than 38,500 people over the age of 60, the group most prone to shingles, a skin and nerve infection.

"I think the results are quite clinically significant," said Dr. Michael N. Oxman, the leader of the study, which is being published today in The New England Journal of Medicine. "There's a major reduction in the overall burden of illness of shingles."

Merck, the developer of the vaccine, has already applied to the Food and Drug Administration for approval, which it hopes to receive by February. It would be the first new vaccine primarily for older adults in 30 years, according to Merck officials.

Shingles is caused by the same virus that causes chickenpox. That virus, called varicella-zoster, is not eradicated from the body when a person recovers from chickenpox, but instead lies dormant in the nervous system and can be reactivated if the immune system weakens.

The shingles vaccine is a much more potent version of the chickenpox vaccine given to children. The vaccine boosts the immune system to keep the virus from being reactivated. It is not expected to help treat people who already have shingles.

It is estimated that more than one million people develop shingles in the United States each year, with both the prevalence and severity of the disease rising as people age. About half the cases each year are in people over 60, so widespread use of the vaccine in that age group could prevent 250,000 cases a year, said Dr. Oxman, an infectious disease specialist at the Veterans Affairs San Diego Healthcare System and the University of California, San Diego.

Shingles, also called herpes zoster, is marked by a rash and pain that can last a few weeks. But some people then develop nerve pain called postherpetic neuralgia, which can be excruciating and last for months or even years. Dr. Oxman said one of his patients, an avid tennis player, had to give up the game because the breeze on her forehead as she ran to the net caused unbearable pain.

There are drugs available for both shingles and for postherpetic neuralgia but they are of limited effectiveness, some experts said.

In the trial, which was conducted by the V.A. health system, with help from the National Institutes of Health and Merck, half of the 38,500 participants received a single injection of the vaccine and the other half a placebo. The volunteers, none of whom had previously had shingles, were then followed for an average of three years and some for as long as five years. The participants, like most adults in the United States, had most likely had chickenpox.

There were 315 cases of shingles in those who got the vaccine compared with 642 among those who got the placebo, a reduction of 51 percent.

Even among those who got shingles, its severity was reduced by the vaccine. The vaccine group as a whole had 61 percent lower burden of illness, a measure of the intensity and duration of pain. And the incidence of postherpetic neuralgia was reduced by two-thirds, with 27 cases among vaccine recipients compared with 80 in the control group.

The authors said that side effects were mild and that they detected no cases in which shingles was caused by the vaccine itself, which contains a live but weakened virus. However, people with compromised immune systems, who might have been at greater risk of getting the disease from the vaccine, were excluded from the trial.

Experts hailed the results. "Grown-ups should welcome the zoster vaccine," Dr. Donald H. Gilden of the University of Colorado wrote in an editorial in The New England Journal of Medicine. "We may need it more than children do."

He predicted that the vaccine would be highly cost effective even if Merck were to charge $500 for it. Merck said it had not decided on the price.

Merck, which has been hurt by the withdrawal from the market of its pain drug Vioxx, is counting heavily on vaccines for growth in the next few years. In addition to the shingles vaccine, it is hoping to bring to market a vaccine against human papilloma virus, which causes cervical cancer, and one against rotavirus, which causes potentially fatal diarrhea, mainly in developing countries.

There are still unanswered questions, like how long the vaccine's effectiveness lasts and whether people younger than 60 might also benefit from vaccination.

Another question is whether adults would bother to get the shot. Only about 60 to 65 percent of people over 65 get flu vaccines each year and only about 40 percent in that age group get the vaccine for pneumococcal disease, said Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University.

But Dr. Schaffner said he thought the shingles vaccine would "galvanize interest in adult vaccination" and would be widely accepted. Shingles he said, "is a life-altering, debilitating disease, and we have the opportunity with this vaccine to cut it in half, maybe even more so."

Dr. Schaffner was not an investigator in the shingles vaccine trial but instead a patient, volunteering to be given a shot at Vanderbilt, one of the clinical trial sites.

A vaccine that cuts the chance of disease only in half might not seem that effective, especially in comparison with vaccines for diseases like polio or measles, which can almost completely prevent the disease.

But Dr. Ann Arvin, a professor at Stanford and expert on the varicella-zoster virus, said that childhood vaccines establish immunity to a virus before a person is infected, while the shingles vaccine is aimed at fighting a virus already in the body, a harder task. That is one reason, she said, that the lower-potency chickenpox vaccine would probably not be able to prevent shingles.

"If one had been trying to predict how effective it would be, this is probably better than I would have guessed," Dr. Arvin, who has consulted for Merck, said of the shingles vaccine.

She and other experts praised the size and design of the study, saying its results were not open to much doubt.