# The Risk of Herpes Zoster Events in Patients with Spondyloarthritis and the Effect of BNT162b2 mRNA COVID-19 Vaccine

## TL;DR

This study examines the risk of herpes zoster in patients with spondyloarthritis and whether the BNT162b2 mRNA vaccine or immunosuppressants influence this risk.

## Contribution

The study provides new insights into HZ risk in spondyloarthritis patients and evaluates the impact of mRNA vaccination and immunosuppressants.

## Key findings

- Psoriatic arthritis patients had a higher HZ incidence rate compared to the general population.
- Jak-I treatment was associated with increased HZ risk in spondyloarthritis patients.
- No significant association was found between the BNT162b2 vaccine and new-onset HZ in SpA patients.

## Abstract

The data on the risk of herpes zoster (HZ) in spondyloarthropathy (SpA) patients are sparse, especially regarding its association with the novel mRNA COVID-19 vaccines and immunosuppressants. We aimed to evaluate whether SpA diagnosis and/or immunosuppressant use affect HZ risk and the influence of mRNA COVID-19 vaccination. We assessed the association between SpA (psoriatic arthritis (PsA) and ankylosing spondylitis (AS)) diagnoses and HZ in a large population database with patients matched by age and sex to controls. We also assessed the association between the COVID-19 vaccine and new-onset HZ using two nested case–control studies, identifying all new HZ cases diagnosed from 1 January–31 December 2021 within the SpA and general population cohorts, matched randomly by sex, age and HZ index date to controls without HZ. Exposure to mRNA COVID-19 vaccination was ascertained in the 6 weeks prior to the index date both in cases and controls. In our results, the incidence rate of HZ was higher in PsA patients vs. the general population, at 1.03 vs. 0.64 per 100 person-years, respectively (adjusted HR = 1.55; 95%CI, 1.19–2.02). Within the SpA group, Jak-I treatment was associated with a higher risk of developing new-onset HZ (adjusted OR = 3.79; 1.15–12.5). Multivariable conditional logistic regression models we used showed no association between COVID-19 vaccination and new-onset HZ among the SpA patients (OR = 1.46; 0.68–3.14).