Background/Purpose:

Increased incidence of herpes zoster (HZ) has been reported in patients with autoimmune diseases.  SLE in particular is known to be associated with a 2-fold increased risk of HZ compared with the general population. ^{1, 2}  Previously available live attenuated zoster vaccine was contraindicated in SLE patients on immunosuppression, or required significant treatment delay, resulting in relatively low vaccination rates. The recently approved recombinant zoster vaccine (RZV) can be safely administered to SLE patients on immunosuppression and recent immunization guidelines recommend RZV vaccination for patients with chronic medical conditions³. Therefore, it is important to define the HZ burden and to identify SLE patients who may benefit from HZ vaccination. We aimed to estimate HZ rates and to compare SLE patients with and without HZ.

Methods:  

Retrospective EMR chart analysis identified all patients with the new diagnosis of SLE, defined as having at least 2 ICD codes for SLE 1-6 months apart between 1/1/2006 and 12/31/2017 and no previous visits with SLE codes in our tertiary care center within 1 year prior. HZ infection was ascertained using ICD codes. HZ rates were calculated in subgroups stratified by SLE-specific medications.  We used univariate analyses to compare patient demographics, laboratory parameters and SLE-specific medications between SLE patients with and without HZ. 

Results:

Out of 1646 patients who met inclusion criteria, 89 (5.4%) were diagnosed with HZ after the initial SLE diagnosis. There were no statistically significant differences between HZ+ and HZ- patients in demographics, baseline leukocyte cell counts, or ICD diagnosis codes for heart failure, cancer, lung disease or diabetes (Table). HZ+ patients were more likely to be on immunosuppresive medications, hydroxychloroquine (HCQ) and corticosteroids (CS). The rate of HZ among 307 patients on CS alone was 8%. The rate of HZ in 230 patients on HCQ +/- CS without other immunosuppressives was 4.8%.  The rate of HZ among 161 patients on mycophenolate mofetil (MMF) +/- HCQ +/- CS without other immunosuppressives was 12%. The rate of HZ among 348 patients on non-MMF immunosuppressives +/- HCQ +/- CS without MMF was 4%. 

Conclusion:

This study demonstrates that among SLE patients treated with MMF, HZ rates were significantly higher when compared to patients receiving other immunosuppression, regardless of CS use. Therefore, HZ vaccination should be considered in all individuals with SLE on MMF. 

References:

1.         Kawai, K., et al., Mayo Clin Proc, 2017: p. 1806-1821.

2.         Gershon, A.A., et al., J Clin Virol, 2010: p. S2-7.

3.         Dooling, K.L., et al., MMWR Morb Mortal Wkly Rep, 2018: p. 103-108.