Freddy Caldera, Mary S. Hayney, Jennifer A. Strople, Arthur Kastl, J Adler, Margie Boccieri, X Zhang, Millie D. Long, M Kappelman
INTRODUCTION: The ongoing US measles outbreak raises concerns for immunosuppressed children with inflammatory bowel disease (IBD). METHODS: We evaluated measles seroprotection in pediatric patients with IBD using a high-sensitivity ELISA (Zeus) compared with a standard commercial assay. RESULTS: Among 176 patients, 173 (98%) were seropositive despite 87% being on immunosuppressive therapy. In comparison, only 163 (93%) were seropositive by commercial assay, resulting in a negative predictive value of 23%. DISCUSSION: Children with IBD have high measles seroprotection. A negative commercial result should not be interpreted as lack of seroprotection, highlighting the need for more accurate assays.