Evaluation of the Safety of Recombinant Zoster Vaccine on Patients with Systemic Lupus Erythematosus in a Tertiary Hospital in Saudi Arabia: A Retrospective Single Centre Study.

INTRODUCTION: Herpes Zoster (HZ) infection is more severe in patients with Systemic lupus erythematosus (SLE). Recent guidelines recommend the Recombinant Zoster Vaccine (RZV) for prevention of HZ in immunocompromised adults aged ≥18 years. RZV has demonstrated efficacy against HZ infection in immunocompromised populations, but data regarding its safety among SLE patients are lacking, especially those who are on biological therapy. OBJECTIVE: Evaluation of the safety of RZV among SLE patients, including patients on biological therapy. METHOD: A retrospective study of 170 patients with SLE who received at least one dose of RZV and 45 unvaccinated SLE patients were included. Data were extracted from the King Fahad Medical City (KFMC) hospital database system. Data analysis was carried out using Statistical methods. RESULTS: A study involved 170 SLE patients who received RZV (90.6% females, with a mean age of 38.5 years and an SLE duration of 8.5±6.2 years). Seventy percent completed two doses of RZV. The mean baseline, post-first-dose, and post-second-dose SLEDAI scores were 3.43±5.27, 3.31±3.11, and 2.97±2.78, respectively, indicating no significant change. A subset of patients was treated with biological therapies, including Belimumab, Rituximab, and Anifrolumab. The incidence of SLE flare within 90 days was 12.9% after the first dose and 12.3% after the second dose. There was a statistically significant association between higher baseline SLEDAI scores and flares after both doses. CONCLUSION: Vaccination with RZV in patients with SLE is safe and not associated with increased SLE activity which is comparable with unvaccinated patients. The reported side effects were mild and comparable to those of the general population.