The chickenpox vaccine is usually given between the ages of 12 and 18 months, but it can be given to older children if they have not had the vaccine or the disease yet. Children age 13 or older should get 2 doses at least 4 weeks apart. This vaccine is 70% to 90% effective in preventing chickenpox. If vaccinated children get chickenpox, they have a much milder form of the disease. By being vaccinated, you can reduce the chance of missed work and school, skin infections, medical costs, and getting shingles later in life.