Humoral Response to Ad26.COV2.S and SARS-CoV-2 mRNA Vaccines in Patients With Inflammatory Bowel Disease

Introduction: Currently, two vaccine platforms have been granted U.S. emergency use authorization for coronavirus disease 2019 (COVID-19) prevention: mRNA (mRNA-1273 (Moderna/NIH), BNT162b2 (Pfizer-BioNTech)) and adenovirus vector (Ad26.CoV2.S (J&J)). We compared humoral responses across these vaccines in patients with inflammatory bowel disease (IBD). Methods: In adults with IBD who received either 2 doses of mRNA-1273 or BNT162b2, or 1 dose of Ad26.CoV2.S, we analyzed plasma antibodies to the viral spike protein receptor binding domain [IgG(S-RBD)] using the SARS-CoV-2 IgG-II assay (Abbott Labs, Abbott Park, IL). We measured antibody levels at dose 1 (D1), dose 2 (D2), and weeks 2 (W2), and 8 (W8) thereafter; IgG(S)≥50 AU/mL was defined as positive response. We excluded those with positive IgG(N) at baseline. We used t-tests to compare mean log-IgG(S) levels at each timepoint. We used multivariable linear regression to adjust for medication and time elapsed between complete vaccination and bio sampling. Results: Of the 353 vaccine recipients 148 (42%), 193 (55%), and 12 (3%) received Moderna, Pfizer and J&J respectively. Demographic and disease characteristics were similar across vaccine groups (Table). By W2, positive antibody levels were detected in 121 (100%), 142 (99%), and 9 (90%) across the respective groups (Figure). Quantitative responses at W2 and W8 were significantly lower among recipients of J&J relative to Moderna and Pfizer (p< 0.0001 each) (Figure). In multivariable analyses, shorter time to measurement, J&J vaccine type, and immunosuppressed status were associated with significantly lower W8 IgG(S) titers. Conclusion: Protective IgG(S) titers were achieved in virtually all vaccine recipients regardless of platform. However, IBD J&J recipients had significantly lower antibody levels than IBD recipients of the mRNA vaccines. Clinical implications of lower but positive antibody titers are unknown but need investigation. Our findings suggest that studies to determine both long term humoral as well as T cell responses to the various vaccine modalities are needed. These studies will inform future management, including booster strategies, in IBD patients as well as in the general population.Figure 1.: Self-efficacy is associated with patient activation and medication adherenceTable 1.: Demographics and biomarkers of initial cohort and follow-up cohort