Effect of 2 vs 3 Doses of COVID-19 Vaccine in Patients With Inflammatory Bowel Disease: A Population-based Propensity Matched Analysis

Aim: There are limited data on the impact of 2 vs 3 doses of COVID-19 vaccine in patients with inflammatory bowel disease (IBD). The primary aim of the study was to assess the efficacy of COVID-19 vaccine based on number of administered doses in patients with IBD. Methods: We conducted a retrospective cohort study using TriNetX, a multi-institutional database to compare patients with IBD who received 1, 2, or 3 doses of BNT162b2 or mRNA-1273 to unvaccinated IBD patients (1.1.2020-7.26.2022) to assess the risk of COVID-19 after 1:1 propensity score matching. We also evaluated the impact of vaccine on a composite of severe COVID-19 outcomes including hospitalization, intubation, intensive care unit care, acute kidney injury, or mortality. Results: After propensity score matching, vaccinated patients with 2 (adjusted OR [aOR], 0.8; 95% confidence interval [CI], 0.6-0.9) and 3 doses (aOR, 0.7; 95% CI, 0.5-0.9) were found to have a lower risk of COVID-19 compared with unvaccinated patients. Vaccinated patients with IBD had a lower risk of severe COVID-19 outcomes (aOR, 0.7; 95% CI, 0.6-0.9) compared with unvaccinated patients. There was no difference in the risk of COVID-19 in IBD patients with 2 compared with 3 doses (aOR, 0.97; 95% CI, 0.7-1.3). However, IBD patients with 2 doses were at an increased risk for hospitalization due to COVID-19 (aOR, 1.78; 95% CI, 1.02-3.11) compared with those that received 3 doses. Conclusion: Vaccinated patients with IBD had a lower risk of severe COVID-19 outcomes compared with unvaccinated patients. A third dose of COVID-19 vaccine compared with 2 doses decreases the risk of hospitalization but not breakthrough infection in patients with IBD.