To qualify, the people need to be over 60 and to have had chickenpox, but not shingles. The reason for this, dating back to a landmark study in 1965, Oxman says, is that the incidence and severity of shingles apparently increases with advancing age. Most of the cases of shingles are seen in patients 60 and older. People who live to age 85 have a 50/50 chance of developing shingles.
The fact that the virus normally lies dormant until the later years suggests that a decreased immunity may play a role in triggering it. In addition, after a person with a healthy immune system gets shingles, they are unlikely to get it again, thus pointing to an immune response.
That's why this study is inoculating subjects with a vaccine similar to the one that's been effective in preventing chickenpox in children. Oxman says, "It doesn't take a lot of virus to do the job in children. What we have done is taken the same attenuated [weakened] virus of the children's vaccine, and just used more of it, nothing very complicated."
The project got underway in March. After inoculation, with either the vaccine or a placebo, the people will be followed for about four years.
"It's fundamentally a very simple-minded study," Oxman tells WebMD. "But there's a lot of work for safety reasons, because if this vaccine works, there's going to be 60 or 70 million older people who are going to want to get it in a relatively short period of time, and the FDA quite properly wants to have a lot more than the usual safety data [for approval]."
Whether this trial works, Perkins of the VZV Foundation tells WebMD, "the problem is going to ultimately be solved by vaccination -- we're pretty sure of that."
- Shingles is an infection of the nerve and skin that can cause excruciating pain for several weeks, months, or years.
- The virus that causes chicken pox is responsible for shingles. It remains dormant in the body after a bout with chicken pox and is triggered by lowered immunity, usually a result of aging.
- A large trial is currently underway to test a vaccine for shingles that is similar to the chicken pox vaccine used in children.