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P460. Immune responses and safety of intramuscular or intradermal trivalent influenza vaccines in patients with inflammatory bowel disease: a randomized controlled trial

W.K. Leung1, T. Tong1, K.H. Chan2, C. Li2, V. Tan1, I. Hung1, 1University of Hong Kong, Department of Medicine, Hong Kong, Hong Kong, 2Queen Mary Hospital, Department of Microbiology, Hong Kong, Hong Kong

Background

Poor immunogenicity of the 2009 influenza A/H1N1 monovalent vaccine has been reported in patients with inflammatory bowel disease (IBD), particularly in those on immunosuppressive agents. The new intradermal (ID) trivalent influenza vaccine has been shown to be equally effective as intramuscular (IM) vaccine in adults and may be superior to IM vaccine in elderly subjects. We compared the immune responses and safety of ID and IM trivalent (HIN1/H3N2/B) influenza vaccine in IBD patients.

Methods

This is a prospective randomized trial conducted in adult patients with stable Crohn's disease (CD) or ulcerative colitis (UC). Subjects were randomly assigned to receive trivalent influenza vaccine given by IM (Vaxigrip, Sanofi Pasteur, France) or ID (Intanza®15, Sanofi Pasteur) route. Randomization was stratified according to the diagnosis of UC or CD. We measured the hemagglutination inhibition (HAI) and geometric mean titres (GMT) at baseline and day 21-post vaccination. IBD disease activity is monitored by Harvey–Bradshaw Index or Simple Clinical Colitis Activity Index accordingly.

Results

This is an interim analysis of the initial 73 patients (35 UC and 38 CD) who had completed the study. The overall day 21-post vaccination seroprotection rate, as defined by HAI titer ≥1:40, was 84.9%, 90.4% and 100% for the respective H1N1, H3N2 and B strains in all patients. There was no significant difference in seroprotection rate, seroconversion rate or GMT-fold increase between the IM and ID groups. Seroprotection rate tended to be higher in IM group for both H1N1 (IM 91.2% vs ID 79.5%; P = 0.2) and H3N2 (94.1% vs 87.2%; P = 0.44). Post-vaccination seroconversion rate, as defined by a 4-fold rise in antibody titer, was also numerically higher in the IM group for H1N1 (76.5% vs 61.5%; P = 0.21). In contrast, the post-vaccination seroconversion rate tended to be higher in the ID group for H3N2 (15.4% vs 5.9%; P = 0.27) and B (56.4% vs 44.1%; P = 0.35). The use of immunosuppressive agents did not appear to alter the seroprotection rate, seroconversion rate and GMT fold changes of the two trivalent vaccines. Transient local reactions were more common with the ID vaccine (87.2% vs 58.8%; P = 0.008) but there was no difference in systemic adverse events (35.3% vs 28.2%; P = 0.6). There were also no significant changes in IBD disease activity after the two trivalent vaccines.

Conclusion

Both IM and ID trivalent influenza vaccines confer acceptable immune responses to IBD patients with no significant adverse effect, and should be recommended to all IBD patients.