Vaccination is the best way to prevent chickenpox. A chickenpox vaccine has been available in the U.S. since 1995 and is easy to get from a doctor or a public health clinic. The chickenpox vaccine is very effective at preventing the disease — between 70% and 90% of people who get vaccinated will be completely immune to chickenpox. If a vaccinated person does get chickenpox, the symptoms will be very mild and only last for a few days.