Importance of vaccination against herpes zoster.

Although herpes zoster is not a reportable condition in the United States, its incidence has been inferred from a variety of studies to range from 3.2 to 4.2 per 1,000 patient-years. This incidence translates into an estimated 1 million cases of herpes zoster annually. Overall, an estimated 32% of persons in the United States will have herpes zoster during their lifetimes. In a recent population-based study in Olmsted County, Minn., researchers found that the incidence of herpes zoster was 3.6 per 1,000 patient-years. The researchers also found that the incidence and rate of complications increased with age, with 68% of cases occurring in those aged 50 years and older. There is a substantial increase in herpes zoster incidence for individuals aged 60 years and older, making the annual incidence in this population approximately 10 per 1,000 patient-years. Herpesviridae have been known to science for many years. The family contains more than 100 types of viruses that infect vertebrates, though only eight types are known to infect humans—herpes simplex virus type 1, herpes simplex virus type 2, varicellazoster virus (VZV), Epstein-Barr virus, cytomegalovirus, and human herpesviruses 6, 7 and 8. Varicella-zoster virus is highly contagious and causes two distinct clinical syndromes—a primary infection that is manifested as varicella (ie, chicken pox) and a secondary latent infection that is manifested as herpes zoster (ie, shingles).