This vaccine is a live but weakened
form of the chickenpox (varicella) virus. Children get the chickenpox vaccine as part of their routine immunizations. Adolescents and adults who are not already immune to the chickenpox virus
can also get the vaccine.
When a weak form of the
virus is injected, the body's immune system reacts. It destroys the virus and
makes disease-fighting proteins (antibodies) to fight the virus. The antibodies
to that virus stay in the body and will keep the person from getting sick or
getting severe symptoms if exposed to the virus again. The person is then
considered immune to chickenpox.