The recent US Food and Drug Administration approval of the vaccine Zostavax, to prevent herpes zoster in people 60 and older, represents a major step in the fight against shingles.

"On the basis of a rather large study we''ve just completed with close to 40,000 people, it seemed to make a significant impact," said Dr Lawrence Gelb of Barnes-Jewish Hospital and the Washington University School of Medicine, both in St Louis.

Dr Gelb, one of the researchers involved in the Veteran''s Administration (VA) cooperative study of an experimental live zoster vaccine, said the new shingles vaccine should help older adults avoid this frequently painful disease, which is usually marked by a blistering rash.

"Depending on how widely it''s embraced by the people in that age group in this country, it may make a startling difference," he said. "It''s difficult to say, but the preliminary data certainly suggest it will help a lot of people. ... It''s just a miserable disease. It will be a significant advance if people don''t have to go through that."

Shingles is rarely fatal.

"It''s almost never actually life threatening," Dr Gelb said. "But it certainly affects the quality of life. Very severe shingles, particularly with the frequent complication of postherpetic neuralgia, can turn a golden retirement into a miserable existence. This degree of severity is unusual, but even mild shingles makes a significant impact."

Overall, 1 in 5 people will have shingles in their lifetime, Dr Gelb said. For people who live to at least age 85, that incidence increases to 1 in 2 people. In people over age 60, more than 11 per 1,000 will have shingles each year. Of the 1 million cases per year, more than half are in people over age 50.

Dr Gelb has been working on the varicella-zoster virus in the laboratory since 1978.

"I''ve long been interested in herpes viruses and the chickenpox virus in particular," he said. "As an internist, my concern has been mostly with shingles, rather than chickenpox, which is primarily a pediatric disease."

Like many scientific quests, serendipity had a hand in Dr Gelb''s decision to study shingles, he said.

"I was mostly working at the bench, trying to ... understand how [the virus] replicated and why it doesn''t grow very well in the laboratory."

That problem still remains largely unsolved, he said. He was subsequently recruited to work on Varivax, the chickenpox vaccine.

"That led to a fair amount of expertise in working with the vaccine virus," he said.

When investigators wanted to determine whether a vaccine similar to Varivax would be useful in preventing or modifying shingles as part of a large VA cooperative trial, Dr Gelb was a natural participant.

"Because I was working in a VA at the time, and because of my previous experience, I was asked to serve as an ad-hoc reviewer when this study was originally proposed for funding," he said. "That was probably back in about 1992. I''ve just been associated with it ever since and served as the principal investigator of the St Louis site."

St Louis was one of 22 sites nationwide involved in the study.

Varivax was approved by the FDA in 1995, Dr Gelb said. Experts thought it had other potential applications.

"People have been thinking a similar vaccine might also work for shingles for, probably, at least 15 years," he said.

The same virus causes both chickenpox and shingles, Dr Gelb said. Well over 90% of adult Americans have had chickenpox, he said. The number of cases of chickenpox in the United States has gone from over 4 million cases a year before 1995 to just hundreds a year now, with many of them imported or in [geographic] pockets where people haven''t been vaccinated.

"This [new vaccine] is going to change the incidence of shingles in ways we don''t know," he said.

There is, Dr Gelb said, a suggestion that shingles incidence decreases as a result of exposure to circulating chickenpox virus in children.

"If that exposure dries up, there will be much less ''immunization'' by this wild-type virus and shingles may actually increase," he said. "However, Varivax seems to be associated with shingles less often than natural infection. How these two competing factors will balance out, I really don''t know. I suspect that shingles will occur less frequently in the future, but I doubt it will be a thing of the past."

The newly approved Zostavax should be available now. Doctors and patients should discuss the vaccination. Formal recommendations by the Advisory Committee on Immunization Practices will be released this fall, but Dr Gelb feels the vaccination is a smart preventive measure.

"A single injection, at ... a reasonable cost, could make an extraordinary impact," he said. "Even if there is no postherpetic neuralgia or other complication of shingles, those 3 to 4 weeks of pain and misery are worth preventing. It appears to be an effective and safe vaccine. The only real downside is the cost."