The association between BNT162b2 vaccinations and incidence of immune-mediated comorbidities

<h3>Background</h3> A large vaccination campaign was initiated worldwide in December 2020 in order to prevent infection with SARS-CoV-2 and severe Covid-19 disease. However, long-term adverse effects of vaccination remain unclear. Therefore, our objective was to examine the association between vaccination and the incidence of autoimmune diagnoses in the first year after vaccine uptake. <h3>Methods</h3> This retrospective cohort study based on Clalit Health Services (CHS) comprehensive database compared the rates of immune-mediated diagnoses among BNT162b2 vaccinated versus unvaccinated individuals. As a reference, a secondary cohort compared individuals infected with Sars-CoV-2 versus uninfected individuals. The minimum follow-up period was 4 months. The cohorts were divided into 4 age groups (12-17, 18-44, 45-64, 65 years or older). Multivariate Cox proportional hazard regression models were applied, followed by a correction for multiple comparisons using the False Discovery Rate (FDR) method, hence accounting for the investigation of multiple clinical outcomes. <h3>Results</h3> Increased risk for immune-mediated diagnoses following vaccination with BNT162b2 was observed for psoriasis in all age groups (HR 1.41-1.69), colitis among patients younger than 65 years (HR 1.38-1.93), vitiligo in patients aged 45-64 (HR 2.82, 95%CI: 1.57-5.08) and for polymyalgia-rheumatica in patients aged 65 years or older (HR 2.12, 95% CI: 1.3-3.47). In the reference cohort, patients who were infected by Covid-19 were at increased risk for fibromyalgia (HR 1.72, 95% CI: 1.36-2.19 in individuals aged 18-44; HR 1.71, 95% CI: 1.31-2.22 in individuals aged 45-64), and hypothyroidism (HR 1.54, 95% CI: 1.15-2.07 in individuals aged 65 years or older). <h3>Conclusions</h3> The BNT162b2 vaccine was associated with increased risk (though rare) for psoriasis, colitis and polymyalgia rheumatica. These findings should be considered as a part of the risk-benefit assessment when planning future vaccination programs for various population groups.