Study shows shingles prevention just a shot away

Washington -- With the conclusion of the Shingles Prevention Study, a 22-site clinical investigation of the effectiveness of a shingles vaccine, came a lot of encouraging and even amazing findings regarding this persistent, puzzling and often painful condition that tends to strike older adults.

But what some of the researchers found most exciting was that the single-shot vaccination seemed to get at the pain.

"It happily reduced the occurrence of postherpetic neuralgia, measured more than 90 days after the beginning of shingles, by two-thirds," said Michael Oxman, MD, national chair of the study and a staff physician at the VA San Diego Healthcare System.

The vaccine also reduced the number of shingles cases by 51% and minimized by 61% the severity of the disease in those who got it despite being vaccinated, Dr. Oxman said. Plus, no serious side effects were reported. The study was published in the June 2 New England Journal of Medicine.

Each year, 600,000 to 1 million Americans are diagnosed with shingles, or herpes zoster. Since about half of those who contract the disease are older than 60, those numbers are expected to rise as the nation's population ages.

Anyone who has had chickenpox could develop shingles. The major risk factors are increasing age and declining immunity. It can take a very mild form, with just a few of its characteristic blisters, or it can be very painful from the start.

"One poor soul had shingles on her chest and ended up getting a cardiac cath because she was thought to have cardiac disease," said Carol Kauffman, MD, chief of infectious diseases at the VA Healthcare System in Ann Arbor, Mich., and an investigator in the trial. But once the typical skin symptoms surfaced, the proper diagnosis was made.

The cause of this great discomfort is the varicella-zoster virus, which had been lying dormant, deep within the nerve cells lined up on either side of the spinal cord. It gained access to these cells, probably decades earlier, after a bout of the chickenpox, which is caused by the same virus.

A waning immune system can cause the virus to wake up and reveal itself through a belt-like sweep of blisters along the strip of skin enervated by an affected sensory nerve.

Although shingles rarely kills, it can be awful, said William Schaffner, MD, professor and chair of preventive medicine at Vanderbilt University School of Medicine in Nashville, Tenn. Dr. Schaffner and his wife were two of the more than 38,500 adults age 60 and older who participated in the randomized, double-blind, placebo-controlled study.

Dr. Oxman also was a participant in his own trial. "I believe in putting my deltoid where my mouth is," he said. Although he initially received the placebo, a subsequent volunteer stint yielded the vaccine.

"For many, shingles is associated with a very discomforting acute illness and it can threaten an eye, but even after the skin rash disappears, the horror of shingles is postherpetic neuralgia that can persist for months or years, and it is a pain that is not readily treatable," Dr. Schaffner said.

Dr. Schaffner and his wife, Lois Knight, were delighted to find out that they received the vaccine, rather than the placebo. They have "re-upped" for another five years to continue to be followed by the investigators who are checking the vaccine's long-term effectiveness.

Adult vaccine track envisioned

If and when the vaccine is approved and recommended for adults -- manufacturer Merck & Co. already has submitted its application for approval to the Food and Drug Administration and hopes to have the vaccine on the market early next year --it could play a role in an expanded adult immunization program.

It then could join the pneumococcal and influenza vaccines to form a trio of preventive strikes against diseases that are particularly serious for older people.

Dr. Schaffner expects that many adults will be interested in receiving a shingles vaccine, and from this interest could spring an integrated adult immunization program similar to that in place for children.

Dr. Schaffner envisions physicians saying to their older patients: "While you're here, we see you need the pneumococcal vaccine, and I would like you in here for a flu shot, and your tetanus booster is due."

Just how many people would line up for a shingles vaccine depends on such factors as awareness and cost.

"There is a subset of older adults who know about shingles and are scared of it, but a lot of people don't even think about it," said Kenneth Schmader, MD, vice chief of geriatrics at Durham VA and Duke Medical Center in Durham, N.C., and an investigator in the trial.

"A lot depends on the cost of the vaccine [which is as yet undetermined by Merck]," said Thomas Weida, MD, a family physician at Hershey Medical Center in Pennsylvania and professor of family and community medicine at Penn State College of Medicine in Hershey. He also would like to know at what age it should be given and whether a booster is needed.

Another intriguing unknown is the role the chickenpox vaccine might play in any future scenario. The gradual disappearance of that disease as more children receive the chickenpox vaccine means that adults will not be receiving a natural, but silent, reinfection when caring for a child with chickenpox, Dr. Oxman said. The belief is that such reinfections boost immunity.

And will children who receive the chickenpox vaccine be as likely to get shingles as they get older? The live virus in that vaccine probably does establish a latent infection that can reactivate to cause shingles, Dr. Schmader said. "But we all feel it will probably be a much milder case, so whether they will need a booster will be an open question."