Baseline Participant Characteristics at Enrollment in the Zoster Eye Disease Study

Purpose: The Zoster Eye Disease Study (ZEDS) is the first randomized clinical trial to study the efficacy of long-term (1 year) suppressive valacyclovir treatment on herpes zoster ophthalmicus (HZO) outcomes. This article details the baseline characteristics of participants. Methods: Setting: The study was set at 95 participating clinical centers in 33 states, Canada, and New Zealand. Study Population: Immunocompetent adults with a history of a characteristic HZO unilateral rash and documentation of an episode of active dendriform epithelial keratitis, stromal keratitis, endothelial keratitis, or iritis within the preceding year, enrolled in ZEDS from November 2017 to January 2023. Intervention: Participants were randomized to double-masked oral valacyclovir 1 gm daily versus placebo for 1 year of treatment and followed for 18 months. Results: Five hundred twenty-seven participants were enrolled across 4 strata according to age at HZO onset (younger or older than 60 years) and duration of HZO at enrollment (less or greater than 6 months), with an even distribution of men and women and a median age of 60 years. More participants with recent (57%, 300/527) than chronic HZO and younger than 60 years at HZO onset (54%, 286/527) were enrolled. Most participants were treated acutely with a recommended antiviral regimen (91%, 480/527) and had not been vaccinated against zoster (79%, 418/527). Conclusions: The broad ZEDS study population enhances the likelihood that ZEDS will provide generalizable high-quality evidence regarding the efficacy and safety of suppressive valacyclovir for HZO immunocompetent adults and whether it should become standard of care. Trial Registration: ClinicalTrials.gov Identifier: NCT03134196.