SARS-CoV-2 breakthrough infections after COVID-19 vaccination in patients with inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND: Patients with inflammatory bowel disease (IBD) have an attenuated serologic response to COVID-19 vaccination. It is unclear whether an impaired immune response in vaccinated IBD patients impacts the susceptibility to SARS-CoV-2 infection and occurrence of severe COVID-19. OBJECTIVES: To evaluate SARS-CoV-2 breakthrough infection rates and the disease course of COVID-19 in vaccinated IBD patients. DESIGN: A systematic literature search and meta-analysis was performed. DATA SOURCES AND METHODS: The search was performed in Embase, Medline, Web of Science Core Collection, Cochrane Central Register of Controlled Trials and CINAHIL. The articles were independently screened and selected by two reviewers. A random-effects model was used to calculate the pooled relative risk for breakthrough infections in vaccinated IBD patients and controls. RESULTS: A total of 16 studies were included, with study periods ranging from January 2020 to October 2021 and follow-up time from 3 weeks to 6 months. The breakthrough infection rates range from 0 to 37.4% in vaccinated IBD patients. The disease course of COVID-19 was generally mild, with low hospitalization and mortality rates (0–8.7% and 0–4.3%, respectively). Vaccinated IBD patients had a significantly lower relative risk of breakthrough infection rate compared to unvaccinated controls (risk ratio: 0.07, 95% CI: 0.03–0.18). No difference was observed between IBD patients and non-IBD controls, and between partially and fully vaccinated IBD patients. The impact of immunosuppressive therapy on breakthrough infection rates differs between studies. Most studies showed no impact from immunosuppressive treatment, anti-tumour necrosis factor alpha or corticosteroids and other biologics; one study reported higher rates for patients treated with infliximab versus vedolizumab. CONCLUSION: Vaccination is effective to prevent COVID-19 infections in patients with IBD. Breakthrough infections do occur, but the disease course is generally mild. Available data seem to suggest a declining trend of breakthrough infections during calendar time. REGISTRATION: The protocol was published in the PROSPERO database (CRD42021292853).