Chickenpox (varicella) is caused by a virus called Varicella-zoster. Chicken pox is a highly contagious illness in children, adolescents, and adults. It starts with a fever and is followed by a rash of red spots that may be itchy. There may be hundreds of these spots, which eventually turn into blisters filled with fluid. After four or five days, the blisters dry out and become crusted. From start to finish, chickenpox may last seven to ten days. Varicella-zoster virus also causes shingles. A vaccine for chicken pox is available.

The virus spreads easily and quickly through personal contact such as touching the blisters. People with chickenpox can also spread the virus through the air when they cough or sneeze. A pregnant woman can pass the chickenpox virus on to her baby before it is born.

For more information see our factsheets:

Chicken pox

Chicken pox vaccine

Chicken pox registration form

Shingles