Keele Research Repository

INTRODUCTION: To investigate the association between vaccination against coronavirus disease 2019 (COVID-19) and inflammatory bowel disease (IBD) flare. METHODS: Patients with IBD vaccinated against COVID-19 who consulted for disease flare between December 1, 2020, and December 31, 2021, were ascertained from the Clinical Practice Research Datalink. IBD flares were identified using consultation and corticosteroid prescription records. Vaccinations were identified using product codes and vaccination dates. The study period was partitioned into vaccine-exposed (vaccination date and 21 days immediately after), prevaccination (7 days immediately before vaccination), and the remaining vaccine-unexposed periods. Participants contributed data with multiple vaccinations and IBD flares. Season-adjusted incidence rate ratios (aIRR) and 95% confidence intervals (CI) were calculated using self-controlled case series analysis. RESULTS: Data for 1911 cases with IBD were included; 52% of them were female, and their mean age was 49 years. Approximately 63% of participants had ulcerative colitis (UC). COVID-19 vaccination was not associated with increased IBD flares in the vaccine-exposed period when all vaccinations were considered (aIRR [95% CI] 0.89 [0.77-1.02], 0.79 [0.66-0.95], and 1.00 [0.79-1.27] in IBD overall, UC, and Crohn's disease, respectively). Analyses stratified to include only first, second, or third COVID-19 vaccinations found no significant association between vaccination and IBD flares in the vaccine-exposed period (aIRR [95% CI] 0.87 [0.71-1.06], 0.93 [0.75-1.15], and 0.86 [0.63-1.17], respectively). Similarly, stratification by COVID-19 before vaccination and by vaccination with vectored DNA or messenger RNA vaccine did not reveal an increased risk of flare in any of these subgroups. DISCUSSION: Vaccination against COVID-19 was not associated with IBD flares regardless of prior COVID-19 infection and whether messenger RNA or DNA vaccines were used.