Effectiveness and safety of the recombinant zoster vaccine in adults aged ≥50 years with inflammatory bowel disease

Adults with inflammatory bowel disease (IBD) face a higher risk of herpes zoster (HZ). We assessed the vaccine effectiveness (VE) of the recombinant zoster vaccine (RZV) in preventing HZ and the risk of flares post-immunization in adults aged ≥50 years with IBD. We conducted a matched cohort analysis at Kaiser Permanente Southern California. To evaluate VE, we included individuals aged ≥50 years with IBD who received 2 doses of RZV between 04/01/2018-12/31/2021 and followed them through 12/31/2022. These individuals were matched up to 1:3 to RZV-unvaccinated individuals on age, sex, race/ethnicity, condition (ulcerative colitis, Crohn's disease), IBD medication type, and index date (date of second dose among vaccinated individuals; same date assigned to unvaccinated match). Cox proportional hazards regression was used to estimate VE. To evaluate safety, we used self-controlled case series analysis (SCCS). The relative risk (RR) of flare was estimated using conditional Poisson regression, comparing the incidence of chart-confirmed IBD new-onset flares in the risk (30 days after each dose) versus comparison periods among individuals with ≥1 dose. In the VE evaluation cohort (2-dose vaccinated: N = 872, unvaccinated: N = 2,550), overall adjusted VE in preventing HZ was 65.1% (95% CI, 24.8-83.8). In SCCS analysis, among 1,199 individuals who received ≥1 dose of RZV, there was no increased risk of IBD flare observed within 30 days after vaccination (RR: 0.80; 95% CI, 0.47-1.35). In adults aged ≥50 with IBD, 2 doses of RZV effectively prevented HZ without increasing flare risk. These findings support current vaccination recommendations to prevent HZ in adults ≥50 years, including individuals with immunodeficiency or immunosuppression.