The varicella vaccine protects against the viral disease commonly known as chickenpox. Chickenpox is caused by the varicella zoster virus. Chickenpox is known for its itchy rash and red spots or blisters (pox) that can appear all over the body. While chickenpox used to be very common, the CDC reports that today the vaccination has a 98 percent success rate. Those who do come down with the chickenpox after being vaccinated typically experience a more mild form of the illness.
