Number of patients with sample proportion, stratified geometric mean titres (GMTs) and exponentiated coefficients of multivariable linear regression model per characteristic
| Variable | Number of patients, n (%) | Seroconversion rate, n/N (%) | GMT (95% CI) | Fold change (95% CI) |
| Age | N/A | N/A | N/A | 0.92 (0.82 to 1.02) |
| Per decade | ||||
| Sex | ||||
| Male | 99 (42.7) | 98/99 (99.0) | 12 947 (10 588 to 15 306) | 0.97 (0.72 to 1.30) |
| Female | 133 (57.3) | 133/133 (100.0) | 15 933 (13 297 to 18 569) | |
| IBD type, n (%) | ||||
| Crohn’s disease | 180 (77.6) | 180/180 (100.0) | 14 835 (12 695 to 16 975) | 0.84 (0.60 to 1.19) |
| UC/IBD-Undetermined | 52 (22.4) | 51/52 (98.1) | 14 049 (10 680 to 17 417) | |
| Medication, n (%)* | ||||
| No immunosuppressives† | 16 (6.9) | 16/16 (100.0) | 13 556 (8142 to 18 971) | – |
| Anti-TNF only | 90 (38.8) | 90/90 (100.0) | 12 861 (9915 to 15 807) | 0.78 (0.43 to 1.40) |
| Immunomodulators only | 6 (2.6) | 6/6 (100.0) | 13 904 (0 to 28 581)‡ | 0.77 (0.28 to 2.15) |
| Vedolizumab only | 21 (9.0) | 21/21 (100.0) | 18 326 (10 785 to 25 867) | 1.65 (0.80 to 3.38) |
| Ustekinumab only | 45 (19.4) | 45/45 (100.0) | 21 038 (16 875 to 25 200) | 1.69 (0.90 to 3.17) |
| Combination therapy | 48 (20.7) | 48/48 (100.0) | 12 449 (8735 to 16 164) | 0.66 (0.35 to 1.24) |
| Oral corticosteroids | 6 (2.6) | 5/6 (83.3) | 2320 (0 to 5728)‡ | 0.07 (0.03 to 0.20) |
| Vaccine type, n (%) | ||||
| Pfizer | 211 (91.0) | 210/211 (99.5) | 14 690 (12 724 to 16 657) | 0.62 (0.37 to 1.02) |
| Moderna | 21 (9.0) | 21/21 (100.0) | 14 341 (10 670 to 18 022) | |
| Vaccine schedule | ||||
| Scheduled | 122 (52.6) | 120/121 (99.2) | 13 520 (11 128 to 15 913) | 0.78 (0.59 to 1.05) |
| Delayed | 110 (47.4) | 110/110 (100.0) | 15 922 (13 147 to 18 696) | |
| Prior COVID-19 | ||||
| Yes | 22 (9.5) | 22/22 (100.0) | 23 470 (16 372 to 30 569) | 1.97 (1.22 to 3.18) |
| No | 210 (90.5) | 209/210 (99.5) | 13 736 (11 898 to 15 573) | |
| Time after vaccine | ||||
| Per week | N/A | N/A | N/A | 0.88 (0.85 to 0.92) |
*IBD medications were classified in the following mutually exclusive groups: A. No immunosuppressive therapies including no medical treatment, use of 5-aminosalicylic acid (oral or topical), and/or oral budesonide; B. immunomodulator monotherapy (azathioprine, 6-mercaptopurine or methotrexate); C. anti-TNF monotherapy (infliximab, adalimumab, or golimumab, originator or biosimilar); D. vedolizumab monotherapy; E. ustekinumab monotherapy; F. combination therapy, defined as any combination of two or more of anti-TNF, immunomodulators, vedolizumab, ustekinumab or tofacitinib; or G. oral corticosteroids, defined as prednisone at any dose alone or in conjunction with any other medication.
†Indicates reference group.
‡Lower bound of CIs that are negative are reported as 0.