The Disease

Varicella, or chickenpox, is one of the most common childhood diseases. It is caused by the varicella-zoster virus. Most people in the United States get chickenpox while they are still children. Until the late 1990's there were about 4 million cases a year. But now that people are using varicella vaccine, that number has begun to drop.

The most recognizable feature of chickenpox is an itchy rash all over the body. Children with chickenpox can also be drowsy and have a fever.

Chickenpox can be spread very easily from person to person. It is spread through the air, by coughing or sneezing, or even talking. It can also be spread by contact with fluid from the blisters. It usually takes 2-3 weeks from the time a child is exposed to chickenpox virus until he or she becomes ill. The disease is contagious from 1 or 2 days before the rash appears until all the blisters are dried up, which usually takes 4 to 5 days.

Chickenpox is usually a mild disease, uncomfortable but not dangerous. Still, serious problems do occur. The blisters can become infected, and some children get encephalitis (infection of the brain). Of every 100,000 infants under one year old who get chickenpox, about 4 die. For older children, 1 to 14 years old, about 1 in 100,000 dies. If a woman gets chickenpox just before or after giving birth, her baby can get very sick, and about 1 in 3 of these children die if they are not treated quickly.

Even when chickenpox is not serious, it can create problems for the family because the parents may have to miss work to care for the sick child. About 1 child out of 500 who get chickenpox must be hospitalized. For adults who get chickenpox, 1 in 50 must be hospitalized.

After a person has chickenpox, the virus stays in the body. Years later, it can cause a painful disease called zoster, or shingles.

U.S. DEPARTMENT OF HEALTH & HUMAN SERVICES
Centers for Disease Control and Prevention
National Center for Immunization and Respiratory Diseases