The Incidence of Herpes Zoster Complications: A Systematic Literature Review

Abstract Introduction The objective of this work was to summarize the incidence of herpes zoster (HZ) complications in different populations. Methods Systematic literature review of PubMed, Embase, and Virtual Health Library records between January 1, 2002 and October 20, 2022 using search strings for HZ, complications, and frequency measurements. Results The review included 124 studies, most conducted in the general population (n = 93) and on individuals with comorbidities (n = 41) ≥ 18 years of age. Most studies were conducted in Europe (n = 44), Asia (n = 40), and North America (n = 36). Postherpetic neuralgia (PHN) was the most studied neurological complication. Variable relative PHN incidence was found in the general population (2.6–46.7%) or based on diagnosis: immunocompromised (3.9–33.8%), depression (0–50%), and human immunodeficiency virus (HIV) (6.1–40.2%). High incidence rates were observed in hematological malignancies (HM) and solid organ malignancies (132.5 and 93.7 per 1000 person-years, respectively). Ocular complications were frequently reported with herpes zoster ophthalmicus (HZO). The relative incidence (incidence rate) of HZO in the general population was reported as 1.4–15.9% (0.31–0.35 per 1000 person-years). High relative incidence was observed in HIV (up to 10.1%) and HM (3.2–11.3%). Disseminated HZ was the most frequently reported cutaneous complication. The relative incidence of disseminated HZ was 0.3–8.2% in the general population, 0–0.5% in the immunocompetent, and 0–20.6% in patients with comorbidities. High relative incidence was reported in HM and solid organ transplant (up to 19.3% and 14.8%, respectively). Discussion Most reported complications were neurological (n = 110), ocular (n = 48), and cutaneous (n = 38). Few studies stratified complications by age or gender (or both). Incidence appeared higher in select immunocompromised populations. Higher incidence was associated with older age in several studies; the general association with gender was unclear. Conclusions Variable incidence of HZ complications was reported by population subgroup. Further research is required to quantitatively analyze incidence by age, gender, and location.