Vaccination Coverage in Adult Patients with Inflammatory Bowel Disease: Impact of a Tailored Vaccination Pathway Including COVID-19 and Herpes Zoster in a University Hospital Vaccination Center.

Abstract

Background/Objectives: Patients with inflammatory bowel disease (IBD) are at increased risk of severe infections, particularly when undergoing immunosuppressive therapy. Vaccination is a key preventive strategy, but coverage in this group is often suboptimal. This study evaluated vaccination coverage among IBD patients at diagnosis/referral and after admission to a structured hospital-based vaccination pathway. Methods: We conducted an observational study (February 2022-February 2025) at the Vaccination Center (VC) of the University Hospital "G. Martino" in Messina, Italy. Adult IBD patients referred by gastroenterologists were assessed for vaccination status using hospital and regional registries, and personalized schedules were developed based on Italian National Vaccine Prevention Plan guidelines. Descriptive statistics were applied to assess baseline and post-intervention vaccination coverage. Results: Of 154 participants (mean age 64 years; 51.9% male), 55.4% were on immunosuppressive therapy. Baseline coverage was heterogeneous: influenza, 6.5%; PCV13, 25.5%; PPV23, 26.6%; herpes zoster, 62.3%; and COVID-19 primary cycle, 79.6%. After enrollment, substantial improvements were observed: influenza, 89.2%; PCV13, 74.5%; PPV23, 67.0%; herpes zoster, 75.4%; and COVID-19 primary cycle, 96.8%. Coverage for catch-up vaccines also improved (e.g., HBV went from 1.9% to 44.2%). However, uptake of COVID-19 booster doses during the study period remained low (15.6%). No significant differences emerged by sex or treatment subgroup. Conclusions: A structured, collaborative care pathway between gastroenterologists and public health specialists significantly improved vaccination coverage among IBD patients. Despite gains, gaps persist in COVID-19 booster uptake and catch-up vaccinations. Integration of vaccination services into routine IBD management is essential to enhance protection in this high-risk population.