| cost effectiveness of herpes zoster vaccine in canada. | herpes zoster (hz), or shingles, results from reactivation of latent varicella zoster virus in the sensory ganglia of adults, and results in significant morbidity in the elderly, including the development of post-herpetic neuralgia (phn). the lifetime risk of hz is about 20-30% and the incidence increases with age. the protective effect of the hz vaccine has been shown in a large clinical trial; however, the effectiveness of the vaccine decreased with age of vaccination. | 2009 | 19908924 |