most cases of chickenpox are relatively mild and run their course in five to 10 days. but it can cause life-threatening complications in infants adults and people with weakened immune systems. before the varicella vaccine was licensed in the u. s. in 1995 there were approximately 100 deaths and more than 11 000 hospitalizations a year from chickenpox. most of the people who died were healthy before they got chickenpox. additionally the illness is highly contagious and can be spread by direct contact or through the air by sneezing or coughing. also someone can get it by coming in contact with fluid from chickenpox blisters.
why do people need a chickenpox vaccine?