Chicken Pox and Shingles
CHICKEN POX AND SHINGLES
Chicken pox (varicella) is a highly infectious, acute viral illness caused by the varicella zoster virus. The illness is characterized by a generalized pruritic, vesicular rash with fever and systemic symptoms usually lasting from seven to ten days. In the pre-immunization era in the United States, there were approximately 4 million cases, 11,000 hospitalizations, and 100 deaths every year. Most cases occurred in children under ten years of age. Complications from chicken pox include pneumonia, encephalitis, cerebellar ataxia, infections, and bleeding disorders. Infants, adults, and immunocompromised persons are at higher risk of severe disease, hospitalization, and death.
Once a person recovers from chicken pox, the virus stays in the body for life (becomes latent), residing in nerve cells known as dorsal root ganglia. The virus can reactivate, resulting in herpes zoster (shingles), which usually presents as a band-like rash in an area of the body that receives innervation from one sensory nerve. Approximately 15 percent of persons who have had chicken pox will develop shingles at some point in their lives, the risk increasing with advancing age. Most cases are associated with a vesicular rash, though some affected persons experience local pain as well. However, persons older than fifty years may develop a severe pain syndrome lasting for months known as post-herpetic neuralgia.
In 1995, a live, attenuated vaccine was licensed in the United States for routine childhood immunization against chicken pox. Since then, the number of cases of chicken pox has decreased significantly. Another vaccine has been tested for prevention or modification of shingles.