Effectiveness of adult zoster vaccination in preventing a first episode of zoster keratitis: A large-scale database study

PURPOSE: The adult recombinant zoster vaccine (Shingrix) has demonstrated effectiveness in preventing herpes zoster ophthalmicus (HZO); however, its effectiveness in preventing zoster keratitis has not been directly evaluated. Given the wide variability in reported keratitis rates among patients with HZO and the potentially sight-threatening nature of this complication, this study was conducted to address this knowledge gap. METHODS: This retrospective, multicenter cohort study was conducted using a global federated electronic health record network. All patients were aged ≥50 years and had no prior diagnosis of zoster ocular disease. The Shingrix-vaccinated cohort was compared with two control groups with no prior Shingrix exposure: patients with presbyopia and patients who received the quadrivalent influenza vaccine. Extensive 1:1 propensity score matching was performed. After matching, 571,746 patients were included in the presbyopia comparison and 626,697 in the influenza vaccine comparison. Primary and secondary outcomes were incident zoster keratitis and conjunctivitis, respectively, over a 5-year follow-up period. Cohort validity was evaluated using positive and negative controls. RESULTS: Shingrix-vaccinated patients demonstrated a significantly reduced risk of zoster keratitis (HR, 0.50; 95% CI [0.37, 0.67]; p < 0.0001) and zoster conjunctivitis (HR, 0.53; 95% CI [0.35, 0.81]; p = 0.0025) when compared with presbyopia controls. Similar results were observed in the comparison with influenza-vaccinated controls, with a reduced risk of zoster keratitis (HR, 0.56; 95% CI [0.39, 0.81]; p = 0.0016) and conjunctivitis (HR, 0.37; 95% CI [0.24, 0.57]; p < 0.0001). CONCLUSIONS: This study supports the potential role of Shingrix in preventing herpes zoster keratitis.