Efficacy of Hepatitis A Vaccination and Factors Impacting on Seroconversion in Patients with Inflammatory Bowel Disease

Background:Little is known about the immune response to hepatitis A virus (HAV) vaccinations in patients with inflammatory bowel disease (IBD). We therefore assessed the immunogenicity of HAV vaccine in patients with IBD and evaluated the impact on vaccination efficacy of immunosuppressants, including corticosteroids, thiopurines, and anti-tumor necrosis factor (anti-TNF) agents.Methods:This open prospective study evaluated the efficacy of HAV vaccination in 419 anti-HAV-negative adult patients with IBD. Patients were vaccinated against HAV at 0 and 6 to 12 months, with seroconversion (anti-HAV immunoglobulin G) measured 1 to 3 months after the second dose.Results:Of the 419 vaccinated patients who finished the study protocol (mean age, 26.9 yr), 355 (84.7%) had Crohn's disease and 64 (15.3%) had ulcerative colitis. The overall seroconversion rate was 97.6% (409/419) but was significantly lower in patients treated with the anti-TNF monoclonal antibody infliximab or adalimumab than in those not treated (92.4% [85/92] versus 99.1% [324/327], P = 0.001). In addition, the seroconversion rate was significantly lower in patients treated with 2 than with <2 immunosuppressants (92.6% [50/54] versus 98.4% [359/365], P = 0.03). When comparing anti-TNF alone with anti-TNF and other immunosuppressants, there was no significant difference in seroconversion rates (odds ratio, 1.2; 95% confidence interval, 0.2-5.6; P = 0.83). The sample/cutoff ratio was significantly lower in patients who did receive anti-TNF therapy than in those who did not (5.5 versus 9.6; P < 0.001).Conclusions:Although HAV vaccination is generally effective in patients with IBD, the seroconversion rate is lower in patients receiving anti-TNF agents (ClinicalTrials.gov registration number NCT01341808).