COVID-19 vaccine-induced immune responses in IBD

Previous studies of patients with IBD undergoing vaccination against infections such as influenza, pneumococcus, and viral hepatitides show variable effects of different immunosuppressive therapies on vaccine immune responses. Anti-SARS-CoV-2 spike protein antibody concentrations and rates of seroconversion following vaccination with either BNT162b2 (Pfizer–BioNTech) or ChAdOx1 nCoV-19 (Oxford–AstraZeneca) are lower in patients with IBD treated with infliximab than in patients with IBD treated with vedolizumab. There are limited data on the effect of other commonly used IBD treatments, including thiopurine monotherapy, anti-IL-12 and anti-IL-23 therapy, and Janus kinase (JAK) inhibitor therapy, on vaccination response. Little is known about how patients with IBD respond to SARS-CoV-2 vaccination compared with non-immunosuppressed, healthy individuals.

VIP was the first study to systematically evaluate antibody responses to SARS-CoV-2 vaccination, both with mRNA and adenovirus vector vaccines, in patients receiving common immunosuppressives used in IBD. We showed that, in addition to the significant attenuating effect of infliximab therapy, vaccine-induced anti-SARS-CoV-2 spike protein antibody responses were significantly reduced in patients treated with tofacitinib relative to healthy controls. No significant reductions in antibody responses were observed in patients treated with vedolizumab, ustekinumab, or thiopurine monotherapy compared with controls.

In addition to patients with IBD who are treated with anti-tumour necrosis factor (TNF) therapies or anti-TNF plus immunomodulator combination therapies, patients who are treated with JAK inhibitors (eg, tofacitinib) have poorer antibody responses to COVID-19 vaccination than do healthy controls, which exposes them to a potential increased risk of SARS-CoV-2 infection. Reassuringly, no significant reductions in antibody responses were observed in patients treated with thiopurines, ustekinumab, or vedolizumab compared with controls. Patients with IBD who are receiving anti-TNF or JAK inhibitors should be prioritised for future booster dose schedules. The VIP study is currently evaluating the impact of third doses on antibody levels and T cell responses.