The Epidemiology of Herpes Zoster in Immunocompetent, Unvaccinated Adults ≥50 Years Old: Incidence, Complications, Hospitalization, Mortality, and Recurrence

BACKGROUND: Data on the epidemiology of herpes zoster (HZ), particularly in the unvaccinated immunocompetent population, are needed to assess disease burden and the potential impact of vaccination. METHODS: The study at a large health care organization comprised: (1) incidence estimated from immunocompetent adults aged ≥50 years unvaccinated with zoster vaccine live who had incident HZ in 2011–2015; (2) proportion of HZ-related nonpain complications assessed by double abstraction of electronic health records (EHRs) of 600 incident patients 2011–2015; (3) HZ-related hospitalizations among HZ patients diagnosed in 2015; (4) HZ-related death determined from automated data and EHRs; and (5) recurrent HZ identified from a cohort initially diagnosed with HZ in 2007–2008 and followed through 2016. RESULTS: HZ incidence rate was 9.92/1000 person-years (95% confidence interval [CI], 9.82–10.01). Proportions of cutaneous, neurologic, and other complications were 6.40% (95% CI,1.73%–11.07%), 0.77% (95% CI, .00%–2.36%), and 1.01% (95% CI, .00%–2.93%), respectively. Only 0.86% of patients had an HZ-related hospitalization. The case-fatality rate was 0.04%. Recurrence rate was 10.96/1000 person-years (95% CI, 10.18–11.79) with 10-year recurrence risk of 10.26% (95% CI, 9.36%–11.23%). CONCLUSIONS: These recent HZ epidemiology data among an immunocompetent, unvaccinated population measure real-world disease burden.