Herpes is a highly stigmatized word. In some circles, it's synonymous with dirty. In others, it's used as an insult. However herpes isn't just one thing. It's a word with several meanings. That's why there isn't a simple yes or no answer to the question of whether chicken pox is herpes, even though it's definitely caused by a member of the herpes virus family.
Herpesviridae is the technical term for the group of viruses colloquially known as herpes viruses. At least five such viruses are known to not only infect humans but to be extremely common. These viruses include:
- HSV-1 - the virus that used to be called the "oral herpes" or "cold sore" virus and is now responsible for a growing number of genital herpes infections, since it can be transmitted during oral sex
- HSV-2 - the virus that used to be responsible for most cases of genital herpes, and still primarily infects the genital region. This is the virus most people are thinking of them when they say someone has herpes.
- Varicella Zoster Virus (VZV) - this is the virus responsible for both the childhood disease known as Chicken Pox and for Shingles - which usually occurs in older adults. Infection with this virus is somewhat preventable via vaccine.
- Epstein Barr Virus (EBV) - this virus causes mononucleosis. It has also been tentatively linked to some cases of chronic fatigue syndrome. However, there needs to be substantially more research before such an association can be confirmed
- Cytomegalovirus - infection by this virus, also known as CMV, is rarely noticed in healthy individuals. However, infection can be quite serious in someone who is immuno-compromised - for instance if they have HIV. CMV infection can also be dangerous during pregnancy, because mothers are much more likely to pass a new infection on to their infants. CMV in infants can cause serious, long-term health problems.
Herpes - The Disease
In general, when someone says that they have herpes, they mean that they have genital herpes. It is technically correct, however, to refer to either genital herpes or oral herpes as herpes. However, infections with the other herpes viruses - CMV, VZV, and EBV - are NOT usually referred to as herpes infections.
So... Is Chicken Pox Herpes?
Getting back to the original question, chicken pox is caused by a herpes virus, but it is not generally thought of as a herpes infection. That may be confusing, but the only reason it seems so important is because of the strong negative connotations people have about the word herpes - feelings that we don't want to apply to a common childhood illness like the chicken pox.
However, chicken pox isn't the only illness caused by a herpes virus that is common in childhood. CMV and EBV occur in young people as well... and so does oral herpes. Until somewhat recently, many (if not most) oral herpes infections were transmitted through casual contact with family members during childhood. Your parents, aunts, or cousins got cold sores, and they loved you, hugged you, and kissed you... so you got them too. As recently as between 1999-2004, 39 percent of American 14-19 year olds were infected with HSV-1, and only a fraction of those infections were likely acquired through sexual behavior. The prevalence of HSV-1 in teens has declined somewhat in recent years, to around 30 percent, but oral herpes is still a common childhood illness -- just like the chicken pox.
There are a few big differences, however. Chicken pox is far more uncomfortable in the short-term... and far less stigmatized in the long-term. It also tends to only reactivate in the body once, if it does so at all. Oh, and it's not primarily transmitted by sex.
Bradley H., Markowtz L.E., Gibson T., & McQuillan G.M. (2013) "Seroprevalence of Herpes Simplex Virus Types 1 and 2—United States, 1999–2010." Journal of Infectious Diseases Advanced Access Publication - Accessed 10/16/2013