Background: Patients with inflammatory bowel disease (IBD) are often immunosuppressed, and those patients receiving anti-tumor necrosis factor α (TNF) therapy can have lower antibody responses to vaccines. Pertussis cases are at their highest levels in the post-vaccine era. There is little data regarding responses to the Tdap (tetanus, diphtheria, and acellular pertussis) vaccine in IBD patients.
Aims: The aim of this study was to compare sustained vaccine-induced Tdap antibody concentrations in a cohort of IBD patients stratified by medication regimens with healthy controls (HC) who had received an adult Tdap booster.
Methods: We performed a cross-sectional study evaluating antibody responses to Tdap vaccine among IBD patients compared to HC. Our study consisted of three patient groups: adults with IBD stratified by maintenance medication regimen: (1) thiopurine monotherapy; (2) anti-TNF monotherapy; and (3) combination therapy (anti-TNF and immunomodulator (thiopurine or methotrexate)).
Results: Ninety IBD patients and 20 HC participated. Pertussis pertactin antibody concentrations were significantly lower in IBD patients (p = 0.021) compared to HC, and those on anti-TNF agents (monotherapy or combination) had lower antibody concentrations compared to those on thiopurine monotherapy (p = 0.028). Diphtheria antibody concentrations were also lower in IBD patients (p < 0.001), and those on anti-TNF agents (monotherapy or combination) had lower antibody concentrations compared to the thiopurine monotherapy group (p < 0.001).
Conclusion: IBD patients on anti-TNF agents had lower antibody concentrations to diphtheria and pertussis. These findings suggest a need for different Tdap booster schedules for IBD patients on anti-TNF therapy. Clinical Trials Registry NCT02434133.
Keywords: Diphtheria; Immunization; Inflammatory bowel disease; Pertussis; Tetanus.