Herpes zoster in frail elderly patients: prevalence, impact, management, and preventive strategies.

Population aging is a worldwide phenomenon with significant and manifold impacts on society. Advanced age correlates with the onset of frailty. In this vulnerable state, the immune response is weakened and a higher susceptibility to infectious diseases is observed. The present narrative review aims to cover the topic of herpes zoster (HZ) and its complications in frail populations. The lifetime risk of developing HZ is estimated at about 20-30%, and the risk increases with age. In older people, HZ can lead to the inability to recover the lifestyle, the interests, and the level of activity that existed before its development. Severity of the disease at presentation and depression are the major correlates of pain burden in patients with acute HZ and postherpetic neuralgia (PHN). The frail elderly need careful assessment prior to treatment initiation and could be affected to a greater extent by treatment-related adverse events. In light of the significant burden caused by HZ and its complications in the frail elderly, the adoption of a preventive strategy appears to be promising, particularly using vaccination in appropriate age- and risk-groups. Although very few vaccine studies consider explicitly the frail elderly as their study population, there is evidence that the live, attenuated vaccine induces significant immunological responses. An adjuvanted recombinant subunit vaccine has recently been approved in Canada, in the United States, in the European Union, and in Japan, and will likely provide additional opportunities for prevention.