Chickenpox is an illness caused by the varicella-zoster virus. The virus is highly contagious and is spread by coming in contact with infected droplets from a cough or sneeze, or by touching the open sores of a person with chickenpox. It is predominantly a childhood illness that can be severe when it occurs in adults and in pregnant women. Most often, symptoms of chickenpox begin with an itchy rash that can spread over the entire body, including the inside of the mouth, around the eyes, and on the genitals. The rash usually begins as red spots, but progress to fluid-filled blisters that will drain and eventually scab over. The rash usually lasts for 7-10 days, and is often accompanied by fever. In 1995, the Food and Drug Administration approved the chickenpox vaccine. It is recommended that children over the age of one year be immunized.