Two years of the COVID-19 pandemic in the population of Czech patients with inflammatory bowel disease treated with biological therapy – experience of the tertiary IBD center

Summary: Background: Inflammatory bowel disease (IBD) may be associated with a more severe course of infections and a different response to vaccination, especially in complicated IBD course and in association with immune-modifying IBD treatment. The aim of this study was to describe COVID-19 pandemic during years 2020–2022 in IBD patients with long-term bio­logical therapy. Methods: A retrospective analysis of SARS-CoV-2 infection incidence in the population of 1,177 IBD (Crohn’s disease or ulcerative colitis) patients with long-term bio­logical therapy (IBD cohort) was performed. The incidence rate, crude incidence rate and standardized incidence ratio of COVID-19 in the IBD cohort, the odds ratio of infection depending on the type of bio­logic therapy administered, the dynamics of COVID-19 incidence depending on the predominant SARS-CoV-2 variant in the population and the current vaccination coverage of the IBD cohort were calculated. Results: From January 2020 to April 2022, 548 confirmed cases of COVID-19 (46.6%) were reported in the IBD cohort, with 39% share of PCR positivity in vaccinated individuals and with 95% occurrence of infection in unvaccinated part of the IBD cohort. Standardized incidence rate ratio of COVID-19 was 27% higher in the IBD cohort compared to the general Czech population. The dynamics of the development of the number of positive cases of COVID-19 in the IBD cohort was identical to the situation in the entire country. A higher odds ratio of the chances of infection was demonstrated in patients treated with tumor necrosis factor inhibitors, but not in patients treated with anti-integrins or monoclonal antibodies against interleukins. In the IBD cohort, 85.2% of patients were properly vaccinated, which was significantly more than the vaccination rate of the entire Czech population. Discussion and conclusion: During the two pandemic years, the incidence of COVID-19 in patients with severe IBD and long-term bio­logical treatment was higher compared to the general Czech population, despite the favorable vaccination coverage of this high-risk patients’ group. A higher risk was associated with tumor necrosis factor inhibitor therapy. Key words: inflammatory bowel disease – Crohn’s disease – ulcerative colitis – COVID-19 – SARS-CoV-2 – vaccination – bio­logical therapy