With respect to hepatitis B virus (HBV) vaccine, not only IBD patients, but other patients with impaired immune function tend to have lower peak anti-hepatitis B (HBs) levels than immunocompetent indivi duals ( 3 ). In the case of IBD patients, the response rate is low, even among those not receiving immunosuppressants or biologic therapy, suggesting that IBD per se could be responsible for the suboptimal serologic response to HBV vaccine ( 3 – 4 ). Adult patients undergoing dialysis and other immunocompromised patients should receive high doses of HBV vaccine to achieve response. For IBD patients in particular, the European Crohn ’ s and Colitis Organization Consensus recommends higher doses of this vaccine for a favorable outcome ( 2 ). A recent study by our group showed an advantage of a doubledose vaccination protocol over the standard dose both in patients with and without immunosuppressive treatment ( 5 ). Th erefore, the double-dose protocol seems to be a suitable option in patients with IBD. Finally, anti-HBs titers can decline to undetectable levels allowing clinically signifi cant HBV infections in immunocompromised responders who do not maintain anti-HBs concentrations > 10 IU / l ( 3 ). It has been recently found that a relevant proportion of patients with protective anti-HBs titers aft er vaccination lose them over time (18 % of patients per year of follow-up), a fi gure that is higher than that reported in the healthy population ( 6 ). Furthermore, the risk of losing protective anti-HBs titers was threefold higher among patients on anti-tumor necrosis factor therapy ( 6 ). In conclusion, given the fact that IBD patients have been shown to have an impaired response to the majority of vaccines and that the response seems to be further diminished with the use of immunosuppressants, vaccines should be administered upon diagnosis of IBD. Furthermore, strategies to increase the effi cacy of vaccines in this population should be investigated.