An operational definition is a clear, concise, detailed definition of a measure. You need operational definitions when collecting all types of data. It is particularly important when a decision is being made about whether something is defective or not defective or whether a defect exists or not.
The varicella vaccine protects against chickenpox (varicella), a common and very contagious childhood viral illness. The varicella vaccine is given by injection when kids are between 12 and 15 months old. They receive a booster shot for further protection at 4 to 6 years of age. Kids who are older than 6 but younger than 13 who have not had chickenpox also may receive the vaccine, with the two doses given at least 3 months apart. Kids 13 years or older who have not had either chickenpox or the vaccine need two vaccine doses at least 1 month apart.
The chickenpox vaccine is a shot that can protect nearly anyone who receives the vaccine from catching chickenpox. It's also called the varicella vaccine, because chickenpox is caused by the varicella-zoster virus. The vaccine is made from a live but weakened, or attenuated, virus.efore the varicella vaccine was licensed in the U.S. in 1995, there were approximately 100 deaths and more than 11,000 hospitalizations a year from chickenpox. The risk of serious, life-threatening complications is greatest among infants, adults, and people with weakened immune systems.