P1333 Patients with Inflammatory Bowel Disease exhibit poor response to Hepatitis B vaccination but maintain protective Measles antibody titres

Abstract Background Patients with inflammatory bowel disease (IBD) are prone to infections due to disease activity, malnutrition, and the use of immunosuppressants.1 Hepatitis B reactivation and severe measles infection are well-known complications of immunosuppression.2, 3 There is a paucity of data regarding the hepatitis B vaccine response among IBD patients in India. The immune status against measles among IBD patients is not well characterised. We aimed to assess the hepatitis B vaccine response and immune status against measles in IBD patients compared with healthy controls and identify predictors of inadequate hepatitis B vaccine response. Methods It is a prospective cohort study done at our centre from December 2021 to April 2025. The cases were IBD patients diagnosed as per European Crohn’s and Colitis Organisation guidelines, and controls were healthy people. Participants with a history of hepatitis B vaccination or positive for hepatitis B surface antigen (HBsAg) or total anti-hepatitis B core antibodies (total anti-HBc) were excluded. Hepatitis B vaccine was given to participants at 0, 1 and 6 months. None of the patients or healthy controls received the measles vaccine during the study period. Blood samples were collected between one and three months after completion of hepatitis B vaccination and tested for hepatitis B surface antibody (anti-HBs) and IgG anti-measles antibody titres. Both the titres were compared between the two groups. Results 43 cases and 43 controls were screened for eligibility. Four cases and twelve controls were excluded because they had a positive anti-HBc status. The final analysis included 39 patients with IBD and 31 healthy controls. An adequate immune response (anti-HBs titre ≥ 10 mIU/ml) was observed in 29 (74.4%) of the IBD patients and 30 (96.8%) of the control group (p = 0.018). Effective immune response (Anti HBs titre ≥ 100 mIU/ ml) was noted in 21 (53.8%) of IBD patients as compared to 30 (96.8%) of the control group (p = 0.001). Thirty-seven (94.9%) of the IBD patients and 28 (90.3%) of the control group had a protective anti-measles antibody titre (measles IgG > 16.5 AU/ml) (p = 0.649). In univariate analysis, serum albumin, faecal calprotectin levels and Crohn’s disease activity index were predictors of inadequate response to hepatitis B vaccination. Conclusion IBD patients showed a poor response to the hepatitis B vaccine but had a similar prevalence of protective measles antibody titers compared to healthy controls. We suggest considering an intensified hepatitis B vaccination regimen for IBD patients who failed to mount an adequate response to routine hepatitis B vaccination. References: 1. Tosca J, Garcia N, Pascual I, et al. Clinical assessment of risk factors for infection in inflammatory bowel disease patients. Int J Colorectal Dis. 2020;35(3):491-500. doi:10.1007/s00384-019-03501-0 2. Loras C, Gisbert JP, Mínguez M, et al. Liver dysfunction related to hepatitis B and C in patients with inflammatory bowel disease treated with immunosuppressive therapy. Gut. 2010;59(10):1340-1346. doi:10.1136/gut.2010.208413 3. Kaplan LJ, Daum RS, Smaron M, McCarthy CA. Severe measles in immunocompromised patients. JAMA. 1992;267(9):1237-1241. Conflict of interest: Dr. Choudhury, Ashis Kumar: No conflict of interest John, Anoop: No conflict of interest Simon, Ebby: No conflict of interest Joseph Anjilivelil, Joseph: No conflict of interest Fletcher, John: No conflict of interest Kannangai, Rajesh: No conflict of interest Abraham, Asha: No conflict of interest Abraham, Priya: No conflict of interest Dutta, Amit Kumar: No conflict of interest