Seroprevalence to anti-SARS-CoV-2, stratified by baseline characteristics
| Variable | Seroprevalence | P value |
| Biological therapy | ||
| Infliximab | 3.4 (161/4685) | <0.0001 |
| Vedolizumab | 6.0 (134/2250) | |
| Biological/immunomodulator therapy | ||
| Infliximab with immunomodulator | 3.0 (78/2639) | 0.00050 |
| Infliximab without immunomodulator | 4.1 (83/2046) | |
| Vedolizumab with immunomodulator | 4.5 (19/424) | |
| Vedolizumab without immunomodulator | 6.3 (115/1826) | |
| Sex | ||
| Female | 4.3 (137/3221) | 1.0 |
| Male | 4.3 (158/3705) | |
| Intersex | 0.0 (0/2) | |
| Prefer not to say | 0.0 (0/7) | |
| Ethnicity | ||
| White | 3.5 (217/6124) | 0.00050 |
| Asian | 9.2 (44/479) | |
| Mixed | 7.7 (12/155) | |
| Black | 13.8 (15/109) | |
| Other | 11.1 (7/63) | |
| Diagnosis | ||
| Crohn’s disease | 3.2 (128/3949) | 0.00050 |
| UC | 5.5 (155/2810) | |
| IBD unclassified | 6.8 (12/176) | |
| Immunomodulators at recruitment | ||
| No | 5.1 (198/3872) | <0.0001 |
| Yes | 3.2 (97/3063) | |
| 5-ASA at recruitment | ||
| No | 3.9 (198/5105) | 0.012 |
| Yes | 5.3 (97/1830) | |
| Steroid use in 2020 | ||
| No | 4.0 (232/5779) | 0.031 |
| Yes | 5.4 (63/1156) | |
| Heart disease | ||
| No | 4.3 (287/6725) | 0.86 |
| Yes | 3.8 (8/210) | |
| Diabetes | ||
| No | 4.2 (280/6623) | 0.57 |
| Yes | 4.8 (15/312) | |
| Lung disease | ||
| No | 4.4 (260/5972) | 0.34 |
| Yes | 3.6 (35/963) | |
| Kidney disease | ||
| No | 4.3 (294/6846) | 0.19 |
| Yes | 1.1 (1/89) | |
| Cancer | ||
| No | 4.3 (293/6885) | 1.0 |
| Yes | 4.0 (2/50) | |
| Smoker | ||
| Yes | 2.2 (16/744) | 0.00050 |
| Not currently | 3.4 (71/2106) | |
| Never | 5.1 (207/4083) | |
| Meets clinical criteria for suspected or probable COVID-19 | ||
| No | 2.5 (158/6345) | <0.0001 |
| Yes | 23.2 (137/590) | |
| Tested with PCR for SARS-CoV-2 | ||
| No | 2.9 (128/4346) | <0.0001 |
| Yes | 6.5 (167/2589) | |
| Positive PCR for SARS-CoV-2 | ||
| No | 3.8 (93/2462) | <0.0001 |
| Yes | 58.3 (74/127) | |
| Positive PCR for SARS-CoV-2 at least 2 weeks prior to serum sample | ||
| No | 3.8 (85/2229) | <0.0001 |
| Yes | 59.0 (69/117) | |
| Hospitalised for confirmed COVID-19 | ||
| No | 4.1 (285/6922) | <0.0001 |
| Yes | 76.9 (10/13) | |
| Shielding behaviour April–July | ||
| I remained in my house or garden | 3.8 (92/2396) | 0.0020 |
| I only left the house for exercise on my own or with members of my household | 3.9 (104/2701) | |
| I encountered people from outside of my household but maintained social distancing | 4.9 (83/1696) | |
| I encountered people from outside of my household but did not maintain social distancing | 11.0 (15/136) | |
| Exposure to documented cases of COVID-19 | ||
| No | 3.1 (192/6160) | <0.0001 |
| Yes | 13.3 (103/773) | |
| Active disease (PRO2) | ||
| No | 4.3 (266/6125) | 0.67 |
| Yes | 3.8 (22/575) | |
Values shown are percentages (proportions).
5-ASA, aminosalicylates; PRO2, patient-reported outcome.