Oh, a shingles discussion! This is definitely something that interests me. I published a paper last year in the journal
Medical Hypotheses about varicella-zoster virus, the virus that causes both chickenpox (varicella) and shingles (zoster.) [Short summary of the article: I proposed that varicella-zoster virus is the cause of many cases of Chronic Fatigue Syndrome, and that it causes Chronic Fatigue rather than shingles when it affects the nerves that control the internal organs. Shingles occurs when varicella-zoster virus attacks nerves that go to the skin.]
Varicella-zoster virus (VZV) is definitely a herpes virus. VZV is sometimes known as Herpes Virus #3. It is fairly similar to Herpes Simplex 1 (a.k.a. Herpes virus #1), which almost everyone has and which causes cold sores, and to Herpes Simplex 2, which causes genital herpes (but is actually one of the less common herpes viruses.) There are 4 other herpes viruses known to commonly attack humans, including Epstein-Barr (Herpes #4, which can cause mononucleosis) and Cytomegalovirus (Herpes #5.)
Herpes viruses are unusual in that they stay in the body forever and can cause infection more than once. VZV is a doubly unusual virus in that it commonly causes more than one type of illness. When people contract the virus for the first time, they get chicken pox. The virus then goes dormant in their body and can reactivate decades later to cause shingles. VZV can also cause some rare forms of brain and spinal cord infections. (About 95% of unimmunized adults in temperate climates have been infected with VZV, so having had shingles or chicken pox doesn't really make you more susceptible to brain infections than everyone else.)
People with shingles can give chicken pox to children who have never had the virus, but they can't directly give shingles to anybody.
...It is my understanding that shingles is a form of herpes virus. For those of us who have had a case of chicken pox at some point in our lives, we now carry the virus, and can get shingles as well.
If this is true, what about the younger generations who aren't getting the virus, but getting vaccinated for chicken pox instead? Does that mean we gave them a vaccination for a virus now, and they will later have to have a vaccination for the virus that the first vaccination gave them?
Well, in temperate climates, almost everyone eventually catches chicken pox if they aren't immunized, so they'd be carrying VZV even if they didn't get the vaccine. More importantly, the chicken pox vaccine (brand name: Varivax) contains a weakened strain of VZV called the Oka strain. (I think it's named for the man who developed it, in Japan.) Generally, the Oka strain is incapable of making people sick. There have been a some cases of children with previously undiagnosed immune problems who have developed chicken pox after getting chicken pox vaccine, but it is rare. So, it is believed that children (with normal immune systems) who get chicken pox vaccine instead of having chicken pox will never get shingles, because their bodies will only carry the weakened, Oka strain of VZV instead of the "wild" strains that can cause illness. (This was a really good question, though!)
The bigger problem with immunizing children against chicken pox is that repeated exposure to chicken pox may help keep VZV under control in older adults, and therefore keep them from getting shingles. Now that fewer children are getting chicken pox, more adults are getting shingles. Shingles is generally a much worse illness than chicken pox. For this reason, some countries (such as the UK) don't recommend that children get the chicken pox vaccine. (Of course, another approach would be to give the chicken pox vaccine to most children and also give older adults the shingles vaccine, which is basically what the US is doing. The drawbacks to this approach are that it costs more and risks side effects from the vaccines.)
Zostavax, the shingles vaccine, also uses the Oka strain of VZV. However, it uses a much higher dose -- something like 14 times as many viral particles as in the chicken pox vaccine. This is the only difference between the two vaccines.