BACKGROUND: Inflammatory bowel disease (IBD) is a chronic disease of the gastrointestinal tract associated with significant morbidity and mortality in children and adults. The treatment of IBD is usually requires chronic immunosuppressive drugs which put the patients at a risk for Hepatitis B virus (HBV) infection and reactivation. Assessment of the HBV immune status has been suggested for children with IBD, and booster vaccination is recommended for the non-immune children. Previous report showed that almost half of patients with IBD had no baseline immunity to HBV and up to 14% could not mount an effective immune response after booster vaccination (Moses J. 2012). The rate of HBV immune status in IBD children living in rural communities of West Virginia has never been reported. Aim: Evaluate the rate of HBV exposure and immunity in a cohort of pediatric patients with IBD and examine the response to HBV vaccine in the non-immune patients.

METHODS: A retrospective chart review of pediatric patients treated for IBD was performed. Hepatitis B surface antigen (HBsAg) and antibody (HBsAb) were checked. Patients found to be non-immune for HBV, received a booster vaccination series and the immune status was rechecked. Immune status was defined at HBV antibody level >10 mLU/mL.

RESULTS: A total of 31 patients with IBD were analyzed. The mean age was 14.5 years; 14/31 (45%) were female. Twenty five (81%) patients were diagnosed with Crohn's disease and 6 (19%) patients had ulcerative colitis. Immunomodulator drugs therapy included: prednisone (n = 17pts), azathioprine (n = 9pts), infliximab (n = 13pts), and adalimumab (n = 7pts). Twenty six (84%) patients were receiving immunosuppressive therapy at the time of analysis. Twenty (65%) patients had no HBV immunity of whom 7 (35%) had prior documentation of HBV vaccine in infancy. At present, booster vaccine was given to 17 (85%) non-immune children, and adequate immune response is available in 16 (92%). Post booster antibody is available in 14 children of whom 13 (92%) achieved adequate antibody level after 2 doses of booster vaccine.

CONCLUSIONS: The majority of our IBD cohort lack protective antibodies and are at risk of HBV infection, even in those with history of vaccination at infancy. Two doses of HBV vaccination provided protective immunity for most of our patients, in spite of immunosuppressive therapy. Careful assessment of the HBV immunity status in children with IBD is vital, and revaccination is recommended in order to achieve full protection for these high risk patients.