Herpes Zoster Reactivation After mRNA and Adenovirus-Vectored Coronavirus Disease 2019 Vaccination: Analysis of National Health Insurance Database.

Background Our study aimed to determine the risk of herpes zoster reactivation and coronavirus disease 2019 (COVID-19) vaccination (mRNA vaccine [BNT162b2] and adenovirus-vectored vaccine [ChAdOx1 nCoV-19]). Methods This retrospective study analyzed herpes zoster cases diagnosed between 26 February 2021 and 30 June 2021 and registered in the National Health Insurance Service database. A matched case-control study with a 1:3 matching ratio and a propensity score matching (PSM) study with a 1:1 ratio of vaccinated and unvaccinated individuals were performed. Results In the matched case control analysis, BNT162b2 was associated with an increased risk of herpes zoster reactivation (first dose adjusted odds ratio [aOR], 1.11; 95% confidence interval [CI], 1.06–1.15; second dose aOR, 1.17; 95% CI, 1.12–1.23). PSM analysis revealed a statistically significant increase in risk within 18 days following any vaccination (adjusted hazard ratio [aHR], 1.09; 95% CI, 1.02–1.16). BNT162b2 was associated with an increased risk at 18 days postvaccination (aHR, 1.65; 95% CI, 1.35–2.02) and second dose (aHR, 1.10; 95% CI, 1.02–1.19). However, the risk did not increase in both analyses of ChAdOx1 vaccination. Conclusions mRNA COVID-19 vaccination possibly increases the risk of herpes zoster reactivation, and thus close follow-up for herpes zoster reactivation is required. [ABSTRACT FROM AUTHOR]