Chickenpox vaccination: Is it 100 percent effective?

No vaccine is 100 percent effective in preventing disease. For the chickenpox vaccine, the Centers for Disease Control and Prevention estimates that nine out of 10 people who are vaccinated with two doses are completely protected from chickenpox. If a vaccinated person does get chickenpox, it's usually a mild case with only a few pox sores that may resemble bug bites instead of the typical fluid-filled chickenpox blisters. However, even a mild infection can be contagious.

In the United States, chickenpox vaccination is a routine childhood immunization. Children receive the first dose between the ages of 12 and 15 months and the second dose between the ages of 4 and 6 years. Adults who have never had chickenpox or who haven't received two doses of the chickenpox vaccine also should get vaccinated.