Chickenpox is a highly contagious viral illness, which in children is usually a fairly mild illness producing a temperature, cough and an itchy rash. Most children miss a week or so of school and quickly return to normal good health. Serious complications such as pneumonia and encephalitis are uncommon. Once infected children have lifelong immunity.
If you buy something through a link on this page, we may earn a small commission. How this works. Many people think of chickenpox as a childhood disease, but adults can get it, too. In a healthy person, the varicella-zoster — or chickenpox — virus usually causes mild symptoms. However, in adults with chronic medical issues, especially those with weakened immune systems, more severe symptoms are possible.
Varicella-zoster is a herpes virus that causes chickenpox, a common childhood illness. It is highly contagious. If an adult develops chickenpox, the illness may be more severe. After a person has had chickenpox, the varicella-zoster virus can remain inactive in the body for many years. Herpes zoster shingles occurs when the virus becomes active again.