Chickenpox is a highly contagious viral infection in which a person develops extremely itchy blisters all over the body and it is common childhood disease caused by a virus in the herpes family of viruses called the varicella virus. The varicella virus can remain in the body for decades and become active again in adults, causing herpes zoster (shingles). Shingles involves the occurrence of painful skin sores along the distribution of nerves across the trunk or face.
Itchy blisters on a red base, progressing to scabs, appear along with newer blisters, mainly on the trunk, face, and scalp and last 5 to 10 days. Other symptoms include fever, headache, tiredness and loss of appetite.The chickenpox rash occurs about 10 to 21 days after coming into contact with someone who had the disease. The average child develops 250 to 500 small, itchy, fluid-filled blisters over red spots on the skin.
Chickenpox vaccine is very safe and effective at preventing the disease. Most people who get the vaccine will not get chickenpox. If a vaccinated person does get chickenpox, it is usually mild—with fewer blisters and mild or no fever. The chickenpox vaccine prevents almost all cases of severe disease.
In Norway compares mortality rates from the period 2002-2007 with trends prior to the introduction of the vaccine.Across all age groups, the death rate from varicella-related illnesses fell from 0.41 per million population in the early 1990s to 0.05 million population in 2007.In the last six years analyzed (2002-2008), a total of three deaths per age range were reported among children aged one to four and five to nine years. In the pre-vaccine era, annual death rates averaged at 13 and 16 deaths, respectively.