What is varicella (chickenpox)?
Chickenpox is an infectious disease caused by the varicella-zoster virus which results in a blister-like rash, itching, tiredness and fever. The rash appears first on the trunk and face, but can spread over the entire body causing between 250 to 500 itchy blisters. Most cases of chickenpox occur in persons less than 15 years old. Prior to the use of varicella vaccine, the disease had annual cycles, peaking in the spring of each year.
