Pubmed information below
http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum
The herpes zoster vaccine is a living attenuated vaccine produced from the OKA/Merck strain already used in the vaccine against varicella. Its safety is good among persons 50 years old and over and its efficiency on lowering herpes zoster incidence, on the burden of illness and on post-herpetic neuralgia has been demonstrated in persons over 60 years old.
FDA site information below:
Who should not be immunized with Zostavax?
People who are allergic to neomycin, or any component of the vaccine should not receive Zostavax.
Zostavax is a live vaccine and should not be given to individuals who have a weakened immune system caused by treatments that they are taking such as radiation, a class of drugs called corticosteroids, or due to conditions such as AIDS, cancer of the lymph, bone or blood.
Zostavax (Herpes Zoster Vaccine) Questions and Answers
http://www.fda.gov/BiologicsBloodVac...ines/UCM070418