P75 Vaccine-induced antibody responses against influenza are diminished in infliximab and tofacitinib-treated IBD patients and correlate with responses to COVID-19 vaccination

IntroductionPatients with inflammatory bowel disease (IBD) are in a risk group recommended for yearly influenza (flu) immunisation. We sought to determine whether immunosuppressive treatments were associated with reduced antibody (Ab) responses to flu vaccination and if these responses correlated with responses to COVID vaccination.Methods266 adults (213 IBD, 53 healthy controls (HC); 165 vaccinated against flu, 101 unvaccinated) were recruited. Medications included infliximab (ifx; n=39), thiopurines (thio; n=43), infliximab and thiopurine combination therapy (combo; n=37), ustekinumab (uste; n=33), vedolizumab (vedo; n=39) or tofacitinib (tofa; n=22). The primary outcome was Ab responses against H3 and H1 flu, stratified by immunosuppressive therapy compared to HC, adjusting for age, and interval between vaccination and sampling.ResultsIn multivariable modelling (figure 1), lower Ab responses against H3 were observed in patients on ifx (Geometric Mean Ratio 0.41 [95% CIs 0.24,0.69], p=0.00096), combo (0.54 [0.32,0.91], p=0.021) and tofa (0.34 [0.17,0.68], p=0.0025) compared to HC. Thio (0.80 [0.48,1.32], p=0.38), uste (0.90 [0.52,1.55], p=0.70) and vedo (0.75 [0.44,1.27], p=0.28) were not associated with lower Ab responses against H3. Reduced Ab responses against H1 were observed in patients on ifx (0.32 [0.17,0.61], p=0.0006), combo (0.38 [0.20,0.72], p=0.0032), thio (0.51 [0.28,0.95], p=0.033) and tofa (0.27 [0.12,0.63], p=0.0026) relative to HC. Uste (0.73 [0.37,1.43], p=0.36) and vedo (0.74 [0.39,1.42], p=0.37) were not associated with reduced Ab responses against H1. Anti-SARS-CoV-2 Ab concentration was moderately correlated with antibodies against H3 (r=0.27; p=0.0004) and H1 (r=0.33; p