Abstract
IntroductionPressure on critical care services because of further COVID-19 surges have forced governments to prioritise primary vaccination to vulnerable groups. To extend limited vaccine supplies, many countries including the United Kingdom have also delayed second vaccine doses, trading maximal effectiveness for a lower level of protective immunity across a greater proportion of the most at-risk population. We investigated whether patients with inflammatory bowel disease (IBD) treated with infliximab have attenuated serological responses to a single-dose of a SARS-CoV-2 vaccine.MethodsAntibody responses and seroconversion rates in infliximab-treated patients (n=865) were compared to a cohort treated with vedolizumab (n=428), a gut-selective anti-integrin α4β7 monoclonal antibody. Our primary outcome was anti-SARS-CoV-2 spike (S) antibody concentrations 3-10 weeks after vaccination in patients without evidence of prior infection. Secondary outcomes were seroconversion rates defined by a cut-off of 15 U/mL, and antibody responses following past infection or a second dose of the BNT162b2 vaccine.ResultsGeometric mean [SD] anti-SARS-CoV-2 antibody concentrations were lower in patients treated with infliximab than vedolizumab, following BNT162b2 (6.0 U/mL [5.9] vs 28.8 U/mL [5.4] P<0.0001) and ChAdOx1 nCoV-19 (4.7 U/mL [4.9]) vs 13.8 U/mL [5.9] P<0.0001) vaccines. In our multivariable models, antibody concentrations were lower in infliximab- compared to vedolizumab-treated patients who received the BNT162b2 (fold change [FC] 0.29 [95% CI 0.21, 0.40], p<0.0001) and ChAdOx1 nCoV-19 (FC 0.39 [95% CI 0.30, 0.51], p<0.0001) vaccines. In both models, age ≥ 60 years, immunomodulator use, Crohn’s disease, and smoking were associated with lower, whilst non-white ethnicity was associated with higher, anti-SARS-CoV-2 antibody concentrations. Seroconversion rates after a single-dose of either vaccine were higher in patients with prior SARS-CoV-2 infection and after two doses of BNT162b2 vaccine (Figure 1).Abstract OFR-8 Figure 1ConclusionsInfliximab is associated with attenuated immunogenicity to a single-dose of the BNT162b2 and ChAdOx1 nCoV-19 SARS-CoV-2 vaccines. Vaccination after SARS-CoV-2 infection, or a second dose of vaccine, led to seroconversion in most patients. Delayed second dosing should be avoided in patients treated with infliximab.