ABSTRACT
Background: While short-term safety data of COVID-19 vaccination has been reassuring, it is theoretically possible that the vaccineassociated immune activation could trigger immune dysregulation and thus exacerbation of IBD. We used the epi-Israeli IBD Research Nucleus (IIRN) database to perform a population-based study exploring the effect of COVID-19 vaccination on disease course in IBD patients. Methods: We included all IBD patients insured in two of the four Israeli HMOs, covering 35% of the population, by validated algorithms, and selected those who received two doses of Pfizer BNT162b2 vaccine. These were matched to unvaccinated IBD patients by demographics, parameters of disease severity at baseline generated by hierarchical clustering of laboratory data, and length of time from previous exacerbation to baseline. The primary outcome was rate of IBD exacerbation as defined by proxies of hospitalizations, treatment escalation, and commencement of corticosteroid or enema. The study period was December, 2020 to June, 2021 Results: 707 pairs of vaccinated and unvaccinated IBD patients were compared. The pairs matched exactly for gender, district, IBD type and disease severity, and ±1 year for age at IBD diagnosis and at vaccination. Mean age was 38.5±13.5 years and median follow-up was 98 days (IQR 16-143). No difference in the outcome was found between the groups from the 2nd vaccination to the end of follow-up, with risk of exacerbation in vaccinated patients of 29% and risk in unvaccinated patients 26% (p=0.3). Conclusion: COVID-19 vaccinated IBD patients demonstrated a rate of IBD exacerbation following vaccination that was no different from that of unvaccinated patients. The multifaceted immune activation induced by the vaccine did not result in worsening IBD disease course. These results provide further reassurance for IBD patients receiving the vaccine.
ABSTRACT
Background: Some studies have shown decreased serological response to vaccination in patients on anti-tumor necrosis factor (TNF) medications. While the large majority of these patients do seroconvert after vaccination, titers have generally been lower and one study showed reduced neutralizing and inhibitory functions. One real-world population- based study compared found no increased infection rate in anti- TNF treated patients, but infection rates were low. The low event rate mandates exploration in longer-term population-based data. We used the epi-Israeli IBD Research Nucleus (IIRN) database to explore the effectiveness of COVID-19 vaccination in IBD patients in Israel. Methods: We included all IBD patients insured in two of the four Israeli HMOs, covering 35% of the population, by validated algorithms, and selected those who received two doses of Pfizer BNT162b2 vaccine. These were matched by date of vaccination ±3 days and demographic variables to non-IBD controls. The primary outcome was incidence of positive COVID-19 PCR following vaccination between December, 2020 to June, 2021. Results: 12,640 IBD patients received two vaccine doses;the matched cohort included 4,946 matched pairs (total 9,892 subjects). Mean age was 50.5±16.1 years and median follow-up was 22 weeks (range 4.1-24.4). Fifteen (0.3%) vaccinated IBD patients tested positive compared with 15 (0.3%) vaccinated non-IBD controls (OR=1 [95%CI 0.49-2.05], p=1.0). Patients on anti-TNF and/or corticosteroids did not have a higher incidence of positivity - neither compared to the entire group nor to IBD patients treated with vedolizumab/ustekinumab, even after precise matching for demographics, underlying diseases and IBD severity. Conclusion: In a large population-based cohort of IBD patients in Israel, vaccine effectiveness was equivalent to non-IBD controls and was not influenced by treatment with anti-TNF or corticosteroids. Notwithstanding previous findings of impaired serological response in anti-TNF treated IBD patients, this real-world large-scale study shows that vaccine protection is robust in IBD patients, including those on immunosuppressive medications.