Herpes Zoster and Its Prevention by Vaccination.

Herpes zoster (HZ; shingles) results from reactivation of varicella-zoster virus (VZV) after primary infection as varicella (chicken pox). It affects mainly older adults and people with immunocompromising diseases or treatments. The most common complication is postherpetic neuralgia (PHN), which has significant adverse effects on quality of life and activities of daily living. Since PHN cannot be prevented once HZ has occurred, and treatment is only modestly successful and is associated with significant side effects, the recent introduction of an effective vaccine is an important achievement. This new vaccine, which combines a single VZV glycoprotein (gE) and a multicomponent adjuvant, is superior to the previously available live attenuated VZV vaccine. The recombinant adjuvanted vaccine is remarkably effective in restoring the protective T cell-mediated immunity required to prevent HZ. Its clinical efficacy is much greater than that observed with other vaccines for older individuals affected by immune senescence, and its safety profile is very acceptable. It has been recommended in the USA and Canada for people who are 50 years of age and older. The immunogenicity and safety of this vaccine in severely immunocompromised individuals, such as after chemotherapy for malignancy, after solid organ or stem cell transplant, and in people with HIV are being studied.