HUMORAL IMMUNOGENICITY OF THREE SARS-COV-2 MRNA VACCINE DOSES IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE

ABSTRACT

Background: Initial studies have shown that patients with inflammatory bowel disease (IBD) have a humoral immune response rate of 95–99% to a two-dose SARS-CoV-2 mRNA vaccine series. A third mRNA vaccine dose has been recommended for the IBD population. The aim of our study was to evaluate the humoral immunogenicity a third SARS-CoV-2 mRNA vaccine dose in patients with IBD. Methods: This was a multicenter, prospective, nonrandomized study comprised of patients with IBD and healthy controls (HC) in the HERCULES cohort. IBD subject eligibility criteria included a diagnosis of IBD, stable doses of maintenance therapy (≥ 2 months), and completion of a two-dose mRNA vaccines series. IBD subjects may have received a third mRNA vaccine dose. HC eligibility criteria included absence of immunosuppressive therapy and completion of a two-dose mRNA vaccine series. HC did not receive a third dose. Those with prior COVID-19 infection were excluded. The primary outcome was total serum SARS-CoV-2 anti-spike IgG antibody concentrations following a third dose compared to antibody concentrations following the two-dose series in IBD subjects. In IBD subjects, we measured antibody concentrations at 28–35 days following completion of the two-dose series and 28–65 days following the third dose. In HC, we measured antibody concentrations at 180 days following completion of the twodose series. Antibody concentrations between groups were compared using Mann-Whitney U tests. Results: One hundred thirty-nine IBD subjects and 46 HC were enrolled. Eightyfive IBD subjects received a third dose (Table 1). One hundred thirty-five IBD subjects (97.1%) had detectable antibody concentrations post-two-dose series, while 85 IBD subjects (100%) had detectable antibody concentrations post-third dose. For IBD subjects that received a third dose, antibody concentrations were significantly higher post-third dose compared to post-two-dose series (median 68 (IQR 32–147) vs 31 (IQR 16–61), p<0.001) (Figure 1). Post-third dose, IBD subjects on systemic corticosteroids or anti-TNF combination therapy had significantly lower antibody concentrations than IBD subjects that were not (median 29 (IQR 10–39) vs 72 (IQR 37–164), p<0.001). For HC, antibody concentrations were significantly lower 180 days compared to 30 days post-two-dose series (median 17 (IQR 11–22) vs 120 (IQR 88–190), p<0.001). HC had lower antibody concentrations 180 days post-two-dose series compared to IBD subjects post-third dose (median 17 (IQR 11– 22) vs 68 (IQR 32–147), p<0.001). Conclusion: All patients with IBD receiving a third SARS-CoV-2 mRNA vaccine dose were seropositive, and median antibody concentrations were higher than those measured after the two-dose series. Patients on corticosteroids and anti-TNF combination therapy had lower antibody concentrations than patients not on such therapy following a third dose. (Table Presented) (Figure Presented)