Background: In patients with inflammatory bowel disease (IBD) on infliximab, data are limited on immune response to influenza vaccine and the impact of vaccine timing. The study aims were to evaluate immune responses to the influenza vaccine in IBD patients on infliximab and the impact of vaccine timing on immune responses.
Methods: In this randomized study, 137 subjects with IBD on maintenance infliximab therapy were allocated to receive the 2012/2013 inactivated influenza vaccine at the time of infliximab infusion (n = 69) or midway between infusions (n = 68). Serum was collected before and after vaccination for hemagglutination inhibition titers. Serologic protection was defined by postvaccine titer of ≥1:40.
Results: Comparing subjects vaccinated at the time of infliximab with those vaccinated midway, serologic protection was achieved in 67% versus 66% to H1N1 (P = 0.8), in 43% versus 49% to H3N2 (P = 0.5), and in 69% versus 79% to influenza B (P = 0.2). Although solicited adverse events were common (60%), no subject experienced a serious adverse event requiring additional medical attention. Only 6% of subjects had a clinically significant increase in disease activity score, not impacted by vaccine timing.
Conclusions: Serologic protection to influenza vaccine is achieved in only approximately 45% to 80% of IBD patients on maintenance infliximab therapy varying by antigen. Yet, importantly, vaccine timing relative to infliximab infusion does not affect the achievement of serologic protection, and the influenza vaccine is well tolerated. Therefore, influenza vaccination at any point during infliximab scheduling is recommended for patients with IBD and opportunities to broaden the availability and convenience of influenza vaccine to optimize coverage should be explored.