P714 Immunogenicity and safety of adjuvated recombinant zoster vaccine in IBD patients on different immunosuppressive therapies

Abstract

Abstract Background Aberrant immune regulation and the use of immunosuppressive therapy make IBD patients more susceptible to complications of primary Varicella Zoster Virus (VZV) infection and significantly increase the risk of Herpes Zoster (HZ). HZ can be prevented by vaccination and RZV is the first HZ vaccine approved for immunocompromised persons. Limited data on immunogenicity and safety of RZV in immunosuppressed IBD patients are available. We investigated humoral and cell-mediated response and safety of RVZ vaccination in IBD patients under different immunosoppressive therapies. Methods In this prospective single centre study, adult IBD patients were enrolled and vaccinated with 2 doses of RZV between May and July 2022. Different immunosuppressive regimens (anti-metabolites, anti-TNF mono and combination therapy; ustekinumab and vedolizumab monotherapy; mofetyl mycofenolate/steroid combination therapy) were not discontinued and the administration schedule maintained. Immunogenicity was evaluated by quantitative detection of serum IgG anti-VZV antibodies and anti-VZV glycoprotein E (gE) antibodies before and 1 month after vaccination completion using ELISA. Reactogenicity was evaluated by diary cards reporting adverse events for 7 days after each dose. Events were graded from 1 (mild, not interfering with everyday activities) to 3 (severe, preventing normal everyday activities). Disease activity was assessed by SCCAI and HBI before vaccination, 7 and 30 days after each dose. Results Vaccination was completed in 104 (98.1%) out of 106 enrolled patients (median age 49.7 years, 59.4% male; 55.7% UC, 44.3% CD). Humoral response was observed in all patients, with a significant increase of anti-VZV antibodies (median UTI 23.8; IQR: 20.2-26.2 vs median UTI 419; IQR: 20.2-26.2, 376-458, p<0.001, median 17.8 fold increase, figure 1) and anti-gE antibody concentration compared to baseline (median OD 0.24; IQR: 0.21-0.26 vs OD 0.53; IQR:0.4-0.6, median 2.3 fold increase, p<0.001, figure 1). Imunosuppressive agents, either in mono or combination therapy, did not influence anti-VZV titre, anti-gE concentration and CMI response. Local and systemic solicited reactions after any dose were reported in 96.2% (grade 3=24.8%) and 88.6% (grade 3=33.3%) of patients respectively, with higher grade of intensity after the second dose. No severe adverse events related to vaccination were observed; 2 patients (1.9%) reported a disease flare. Conclusion RZV vaccine is able to induce a robust gE-specific humoral immune response. The type and intensity of immunosuppressive regimens did not influence humoral immunogenicity. RZV vaccination was safe and well tolerated in terms of both reactogenicity and exacerbation of disease.