Topic: The incidence and morbidity of herpes zoster (HZ) and HZ ophthalmicus (HZO), and the potential impact of varicella vaccine on their epidemiology.

Clinical relevance: Herpes zoster affects 20% to 30% of the population at some point in their lifetime; approximately 10% to 20% of these individuals will have HZO.

Methods: The peer-reviewed literature published from 1865 to the present was reviewed.

Results: Herpes zoster is the second clinical manifestation of varicella-zoster virus (VZV). The incidence and severity of HZ increase with advancing age. Varicella-zoster virus-specific cell-mediated immunity, which keeps latent VZV in check and is boosted by periodic reexposure to VZV, is an important mechanism in preventing VZV reactivation as zoster. Thus, widespread varicella vaccination may change the epidemiology of HZ. Herpes zoster ophthalmicus occurs when HZ presents in the ophthalmic division of the fifth cranial nerve. Ocular involvement occurs in approximately 50% of HZ patients without the use of antiviral therapy. There is a long list of complications from HZ, including those that involve the optic nerve and retina in HZO, but the most frequent and debilitating complication of HZ regardless of dermatomal distribution is postherpetic neuralgia (PHN), a neuropathic pain syndrome that persists or develops after the zoster rash has resolved. The main risk factor for PHN is advancing age; other risk factors include severe acute zoster pain and rash, a painful prodrome, and ocular involvement. Many cases of HZ, HZO, and PHN can be prevented with the zoster vaccine.

Conclusion: Vaccination is key to preventing HZ, HZO, and PHN, but strategies for both varicella and HZ vaccines will need to be evaluated and adjusted periodically as changes in the epidemiology of these VZV diseases become more evident.