ANTI-SARS-COV-2 VACCINATION AND ANTIBODY RESPONSE IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE ON IMMUNE-MODIFYING THERAPY. PROSPECTIVE SINGLE TERTIARY CENTER STUDY ON 602 IBD PATIENTS

Patients with inflammatory bowel disease (IBD) on immune-modifying treatment could be at an increased risk for severe coronavirus disease of 2019 (COVID-19), thus data on the efficacy and safety of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccines are essential. We have conducted a prospective study of IBD patients vaccinated with BNT162b2, CX-024414 and ChAdOx1 nCoV-19 vaccines. The aim was to evaluate the rate and the magnitude of seroconversion, to assess the effect of different immune-modifying treatment modalities on the magnitude of anti-SARS-CoV-2 IgG antibody levels, and to analyze the impact of anti-SARS-CoV-2 vaccination on the inflammatory biomarkers of IBD.

The study included 602 IBD patients and 168 immunocompetent health-care workers serving as controls. Serum anti-SARS-CoV-2 IgG antibodies were measured by chemiluminescent microparticle immunoassay before the vaccination, and 8 weeks after the end of vaccination.

Of IBD patients, 82.2% were receiving biological treatment: most of them were treated TNF-alpha inhibitors (48.5%) and just under half of them with concomitant thiopurines or methotrexate, followed by vedolizumab (18.6%) and ustekinumab (15.1%). Only 8.1% of patients were on 5-aminosalicylates, and a minority (2.2%) were treatment-free. The post-vaccine seropositivity rate among IBD patients and controls was 97.8% versus 100%. Median anti-SARS-CoV-2 IgG levels were lower among IBD recipients of ChAdOx1 nCoV-19 compared to two other vaccines (p < 0.0001) and to control ChAdOx1 nCoV-19 recipients (p = 0.01). No correlation was found between serum trough levels and anti-SARS-CoV-2 IgG concentrations for any of the biological drugs used. TNF-alpha inhibitors with concomitant immunosuppressive treatment but no other treatment modalities were associated with the lower post-vaccination antibody response ( p <0.0001). When evaluating the laboratory activity of IBD by C-reactive protein and fecal calprotectin levels, no significant differences were found before the vaccination and eight weeks after its completion.

Our findings warrant particular attention to the anti-SARS-CoV-2 vaccination of IBD patients treated with TNFa inhibitors with concomitant immunomodulators and show priority of mRNA vaccines in this specific group of patients.