Is chickenpox so bad, what do we know about immunity to varicella zoster virus, and what does it tell us about the future?

Varicella and zoster continue to cause significant morbidity and even mortality in children and adults. Complications include bacterial superinfection, central nervous system manifestations such as meningitis, encephalitis, and cerebellar ataxia, and pain syndromes especially post herpetic neuralgia. Many developed countries but not all, are now administering live attenuated varicella vaccine routinely, with a decrease in the incidence of disease, providing personal and herd immunity. There is some controversy, however, in some countries concerning whether a decrease in the circulation of wild type virus will result in loss of immunity to VZV in persons who have already had varicella. This manuscript reviews the complications of varicella and zoster in detail, the reasons for development of vaccines against these diseases, complications of vaccinations, and mechanisms by which immunity to this virus develops and is maintained. There are strong indications that the best way to control disease and spread of this virus is by vaccination against both.