<scp>COVID</scp> ‐19 infection risk between vaccinated patients with inflammatory bowel disease: A hospital‐based retrospective cohort study in Central Taiwan

Abstract Coronavirus disease 2019 (COVID‐19) vaccines are effective in preventing severe disease in patients with inflammatory bowel disease (IBD), but the risk of infection following vaccination in ulcerative colitis (UC) versus Crohn's disease (CD) patients remains unclear. This study compares the risk of COVID‐19 infection between UC and CD patients postvaccination. A retrospective cohort study was conducted on IBD patients who received at least two doses of the COVID‐19 vaccine at China Medical University Hospital between January 1, 2020, and October 31, 2024. The study included 169 IBD patients (96 UC, 73 CD). Demographic data, vaccination history, and medical records were analyzed. Logistic regression assessed the odds of COVID‐19 infection, adjusting for potential confounders. UC patients were significantly older than CD patients (44.92 ± 13.72 years vs. 37.27 ± 15.27 years, p = .0008). The overall prevalence of COVID‐19 infection was 49.11%, with UC patients having a significantly higher infection rate (56.25%) compared to CD patients (39.73%, p = .0333). Logistic regression showed UC patients had an odds ratio of 1.95 (95% confidence interval [CI] = 1.05–3.62) and an adjusted odds ratio of 2.78 (95% CI = 1.20–6.44), indicating a 1.95‐ to 2.78‐fold higher risk of infection. A trend toward reduced infection risk with more vaccine doses was observed, with medication use not significantly affecting infection risk. Our study showed that vaccinated UC patients had a significantly higher risk of COVID‐19 infection compared to CD patients, highlighting the need for tailored monitoring and care strategies for UC patients, even postvaccination.