Shingles Vaccine Shows Promise

June 1, 2005 — -- A new vaccine has been found to greatly reduce the risk of shingles -- a painful, debilitating reincarnation of the chicken pox virus, which affects hundreds of thousands of U.S. adults each year.

The study, released today in The New England Journal of Medicine, followed 38,000 people over the course of three years. The vaccine reduced the number of shingles cases by 50 percent and reduced the incidence of pain from shingles by more than 60 percent.

While shingles can affect anyone who has had chicken pox, it most strikes adults over 60 years old, said Dr. Steven Black, director of the Kaiser Permanente Pediatric Vaccine Study Center in Oakland, Calif.

"As our population ages and there are more people with immunosuppressive conditions such as cancer and HIV that are surviving, shingles is becoming more of a problem," he said.

The study, led by Dr. Michael Oxman of the VA San Diego Health Care System in San Diego, Calif., comes after nearly 14 years of research by many institutions.

"As a physician, it was frustrating to have patients with postherpetic neuralgia [shingles pain] and not be able to do anything about it," said Oxman. "So I thought, if you can't treat it, you'd better prevent it."

Weighing the Risks

Approval by the Food and Drug Administration is still pending, but physicians have high hopes that it will soon be widely used in older adults.

"Every person 50 years or older should get vaccinated," said Dr. Donald Gilden, head of the department of neurology and a shingles researcher at the University of Colorado Health Sciences Center in Denver.

Gilden has suffered from shingles and is excited that his patients will soon be spared the same agony.

"Unlike chicken pox, shingles hurts. It hurts very badly," he said.

The pain can be crippling and in some cases shingles is fatal. Medications to treat the pain of shingles are largely ineffective. The infection may also move into the spinal cord, causing brain damage.

Patients did experience some redness and pain at the injection sight. Serious side effects, however, occurred in fewer than 2 percent of people studied -- similar to those who received a placebo.

Mimicking Mother Nature

The vaccine is essentially identical to the childhood vaccination for chicken pox, only given at a higher dose. It is manufactured by Merck Pharmaceuticals, the financial backer of the study.

After a bout of chicken pox, the virus takes up a lifelong residence in the nerve cells. As long as the body's immune system remains healthy, the virus will be kept in a state of suspended animation.

But when the immune system begins to falter, due to old age or diseases like AIDS and cancer, the virus reawakens.

Traveling to the point where the nerves reach the skin's surface, the virus causes a red rash to bloom, spotted with painful blisters. The rash usually subsides in a few weeks, but for many patients, the virus continues to aggravate the nerve cells and causes a tremendous amount of pain.

Since 1965, doctors have known that people who get shingles once usually don't get it again. Oxman and others thought that coming down with shingles might actually kickstart the body's flagging immunity to the virus.

"We've largely tried to imitate Mother Nature with the vaccine," said Oxman. By injecting adults with an inactive version of the virus, researchers essentially mimicked the disease, causing the patient's natural immunity to amp back up.

During his medical training, Oxman was inspired to do vaccine research by Dr. John Enders. Enders, a Nobel Prize winner, grew the polio virus in his laboratory, laying the groundwork for the development of the polio vaccine.

Lingering Immunity? A Lingering Question

Questions still remain as to how long the immunity will last.

"There's no way to predict that," said Oxman, but previous research indicates that receiving a booster shot of the vaccine may be safe. The patients from this trial will have to be followed for several more years to reach a definite answer.