Inadvertent live vaccine administration in adult patients with inflammatory bowel disease on immunosuppressive therapy.

Live vaccines are contraindicated in patients on immunosuppressive therapy. We conducted a retrospective study evaluating the administration of a live vaccine in patients with IBD on immunosuppressive therapy. The primary outcome was to determine clinical or disseminated disease episodes within three months of vaccine administration in patients who inadvertently received a live vaccine. Thirty-five patients met the inclusion criteria. Twenty-two received the measles, mumps, and varicella (MMR) vaccine, nine received the live zoster vaccine, and one received the varicella vaccine (VAR). Three patients received both the MMR and VAR. The majority of our cohort (20, 57 %) were on anti-tumor necrosis factor, followed by azathioprine (12, 34 %) and vedolizumab (3, 9 %). Although live vaccines are contraindicated in patients on immunosuppressive therapy, none of the patients in this study reported any infections after inadvertent immunization. Further studies are required to address the safety and effectiveness of live vaccine administration in this population.