2300. Incidence, Complications, and Recurrence of Herpes Zoster in Unvaccinated Adults ≥50 Years of Age

Background More recent baseline epidemiological data for Herpes Zoster (HZ) in adults ≥ 50 years of age, obtained before the introduction of the adjuvanted Recombinant Zoster Vaccine (RZV), are needed for future evaluations of the impact of RZV on HZ epidemiology. Methods The study comprised five elements: (1) The incidence of HZ was estimated from immunocompetent adults ≥ 50 years of age not vaccinated with Zoster Vaccine Live who had incident HZ between 2011–2015. HZ was identified by International Classification of Diseases (ICD) codes from electronic health records (EHR) of 4.6 million Kaiser Permanente Southern California members; (2) Postherpetic neuralgia (PHN) was identified by validated survey and medical record review of laboratory-confirmed incident HZ cases recruited during 2012–2015 for HZ-related pain ≥ 90 days after initial HZ diagnosis; (3) HZ Ophthalmicus (HZO) with ocular complications was identified by ICD codes and keyword search in EHR among patients identified with HZO using a validated natural language processing algorithm; (4) The proportion of HZ-related non-PHN and non-HZO cutaneous, neurological or other complications was assessed by double abstraction of EHRs from a sample of 600 incident HZ cases; (5) Recurrent HZ was identified by having an HZ diagnosis with HZ antiviral medication ≥ 6 months after the most recent HZ diagnosis with HZ antiviral medication in a cohort initially diagnosed with HZ between 2007 and 2008 and followed through 2016. Results We identified 40,893 incident HZ cases with an overall incidence of 9.92 (95% confidence interval [CI]: 9.82–10.01) per 1000 person-years. The proportion of incident HZ cases with PHN and HZO with ocular involvement was 18.37% (95% CI: 14.90–21.84%) and 8.06% (95% CI: 7.80–8.32%), respectively. The proportion of cutaneous, neurological, and other complications was 7.20% (95% CI: 5.44–8.96%), 0.87% (95% CI: 0.79–0.95%), and 1.24% (95% CI: 1.15–1.33%), respectively. The incidence of recurrent HZ was 10.96/1000 person-years (95% CI: 10.18–11.79). Conclusion HZ is common among unvaccinated US adults ≥ 50 years of age, with PHN and HZO occurring most frequently among incident HZ cases. Funding GlaxoSmithKline Biologicals SA, GSK study identifier: HO-17-18378. Disclosures All authors: No reported disclosures.