P-220 To Assess the Rate of Adequate Immune Response to Primary Hepatitis B Vaccination Series in Patients with IBD

Abstract

Background: Patients with inflammatory bowel disease (IBD) are often placed on immunosuppressive medications which put them at a potential risk for reactivation of hepatitis B (hep B). Immune response following hep B vaccination is reported to be around 90% in children from the general population. The aim of this study was to assess the rate of adequate immune response to primary hep B vaccination series in patients with IBD. Method(s): We performed a retrospective chart review of patients with IBD who had serologic samples tested for hepatitis B surface antigen (HbsAg) and hepatitis B surface antibody (HbsAb) from February 2012 to July 2015. The study was conducted at Yale New Haven Children's hospital. Patients up to 22 years of age were included. Adequate immune response to hep B was considered to be present when the HbsAb level was above >=8 mIU/mL by our laboratory standard. Age, gender, BMI (presence of obesity), type of IBD, and medications were noted to assess association of these factors with inadequate response to hep B vaccination. Result(s): HbsAg and HbsAb levels were tested in 98 children with IBD. Mean age of the patients was 16 (+/-3) years; 37 females and 61 males. Thirty-seven patients had ulcerative colitis and 61 patients had Crohn's disease. None of the patients had a positive HbsAg. Sixty-three (64%) patients were found to be non-immune to hep B with HbsAb level less than 8 mIU/mL. In 35 children with an adequate immune response, the mean level of HbsAb was 91 mIU/mL (range 9 to 560 mIU/mL). Sixty one percent of patients receiving anti-TNF therapy had an inadequate immune response to Hep B. Use of infliximab (24% in non-immune group versus 16% in immune group) or immunomodulators (15% in non-immune group versus 8% in immune group) was not significantly different between the 2 groups. Factors such as gender, type of IBD, presence of obesity were also not significantly different in the non-immune and immune group. Conclusion(s): Immunity to hepatitis B after primary vaccination series is lower in patients with IBD as compared to the known immune response in the general population (64% versus 90% respectively). Use of immunomodulator or anti-TNF therapy is not associated with lack of immune response to hepatitis B vaccine.