Vaccination is recommended for 12 year olds who have never had chickenpox and can be withheld if they have had chickenpox. The varicella vaccine is made from an infectious strain of the chickenpox virus and is effective in preventing the occurrence of chickenpox. Also, if you have had chickenpox in the past, you will usually not need to be vaccinated against chickenpox because you will have a longer-lasting immunity to chickenpox after you have recovered from the disease. If the child is 12 years old and has never had chickenpox before, it is recommended that the vaccine be given twice, with an interval of 6 to 10 weeks between doses, to ensure longer lasting immunity, usually for 5 years or more. In conclusion, it is recommended to consult a medical professional before receiving the vaccine and to complete the vaccination process in a standardized manner.