P318 Intra-dermal with topical imiquimod pre-treatment versus intra-muscular hepatitis B vaccination in inflammatory bowel disease patients: a double-blind randomized controlled trial

Abstract

Abstract Background Patients with inflammatory bowel disease (IBD) are often immunocompromised and at risk of various opportunistic infections including viral hepatitis. Vaccination is recommended to prevent hepatitis B infection, but efficacy with conventional intra-muscular hepatitis B vaccination in IBD patients is suboptimal. Intra-dermal vaccination has been shown to be an effective way in augmenting immune response in poor vaccine responders. In addition, topical imiquimod, a synthetic agonist of toll-like receptor 7, has been shown to further boost the immunogenicity when applied to the injection site before intra-dermal vaccination. Our study compared the efficacy of intra-dermal hepatitis B vaccination with topical imiquimod with conventional intra-muscular hepatitis B vaccination in IBD patients. Methods This is a double-blind, randomized-controlled trial. IBD patients with no evidence of active or past infection nor history of vaccination i.e. negative serology to all HBsAg/Anti-HBc/Anti-HBs were recruited. They were randomized in 1:1 ratio to receive either intra-dermal recombinant hepatitis B vaccine with topical imiquimod pre-treatment to site of injection (ID) or intra-muscular recombinant hepatitis B vaccine with topical aqueous cream (IM). Same dose (20mcg) of vaccine (Engerix B, Glaxo Smith Klein) was administered to both groups at 0, 1, 6 month. The primary outcome was the sero-protection rate at 12-month, defined as percentage of recruited subjects with anti-HBs titre ≥ 10 mIU/mL. Results 104 patients (mean age 46; 68% male; 50% Crohn’s and 50% UC) were enrolled, with 53 received ID and 51 received IM vaccine. The percentage of patients using steroids, immunomulators and biologics at the time of randomization was 15, 55 and 22 %, respectively. Baseline demographic, disease characteristic, and laboratory parameter were comparable between the ID and IM groups. Sero-protection rate at 12-month was significantly higher in the ID arm compared to the IM arm (91% vs. 69%, P=0.005; Figure). Percentage of good responders at 12 month (anti-HBs titre > 100 mIU/mL) was also higher in the ID arm than in the IM (77% vs 59%, P=0.042). Multivariate analysis showed that use of ID vaccine (OR 4.45, 95% CI 1.40-14.47) and a higher albumin level (OR 1.30, 95% CI 1.06-1.58) are associated with better sero-protection rate. There was no significant difference in adverse effects reported in (64% in ID vs 55% in IM; Table). Conclusion ID hepatitis B vaccination with topical imiquimod is safe and offers superior seroprotection against hepatitis B among IBD patients.