Noninfectious Uveitis Risk After COVID-19 Vaccination: A Nationwide Retrospective Cohort Study

Purpose: To investigate the incidence and risk of noninfectious uveitis (NIU) following COVID-19 vaccination compared with an unvaccinated, uninfected control group. Design: Retrospective population-based cohort study. Methods: We included 5,185,153 individuals who received the first vaccine dose in the exposed group and 2,680,164 individuals in the unexposed, uninfected control group. The study observed for 180 days from their index date. Cumulative incidence and risk of NIU following COVID-19 vaccination, and attributable risk factors were assessed. Results: Multivariable analysis showed elevated risk of nonanterior NIU within 60 days (hazard ratio [HR] 1.27 [95% confidence interval {CI} 1.03-1.55] and 61-180 days (HR 1.39 [95% CI 1.20-1.62]). Subgroup analysis highlighted an increased risk in females for early and delayed nonanterior uveitis (HR 1.44 [95% CI 1.08-1.92]; HR 1.78 [95% CI 1.43-2.20], respectively). Regardless of the location and onset timing of uveitis, a history of NIU was identified as the most significant risk factor, with a high hazard ratio ranging from 100 to 200. Conclusions: COVID-19 vaccination may modestly increase the risk of nonanterior uveitis especially in females. Despite adjustments, bias may persist in the exposed group, owing to significant differences between unexposed and exposed groups and low incidence of nonanterior uveitis in the unexposed group. Future research should aim to refine these findings by assessing uveitis risk in prior NIU patients and by enlarging the sample size or cohort matching.