Zostavax Vaccine is a medicine used in adults 50 years of age or older to prevent herpes zoster (also called shingles). It contains a weakened chickenpox virus (varicella-zoster virus). It works by helping your immune system protect you from getting herpes zoster. It is given by a healthcare professional and should not be self-administered. It prevents the nerve pain that can follow herpes zoster (shingles) in some people. It does not protect everyone, so some people who get the vaccine may still get the disease. It cannot be used to treat herpes zoster or the nerve pain that may follow shingles, once you have it. The most common side effects of this medicine include redness, pain, itching, swelling, or bruising where the shot was given. It may also cause fever, headache, and upper respiratory tract infection. If these side effects do not go away with time or get worse, let your doctor know. Your doctor may help with ways to reduce or prevent these symptoms. To make sure the vaccine is safe for you, before receiving the vaccine, it is important to let your doctor know if you have any problems with your heart, liver, or kidneys. You should also tell your doctor about all the medicines you are taking.