Background and Aims

Mass vaccination against SARS-CoV-2 has been the most effective strategy to combat against COVID-19 pandemic. However, different immune-mediated diseases, including cases of myocarditis or glomerulonephritis (GN) have been reported, being anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitis one of the possible side effects caused by the mass-scale vaccination.

Our aim was to evaluate the incidence of new ANCA positive patients during 2021 in comparison with 2019, before the pandemics.

Methods

This retrospective study included patients from University Hospital Marqués de Valdecilla (reference population: 580,000 inhabitants) who debuted with ANCA (anti-MPO, anti-PR3), and/or anti-MBG antibodies during 2021 discarding the presence of inflammatory bowel disease and who received vaccination against SARS-CoV-2. Likewise, patients who debuted with these autoantibodies in 2019 were also included in order to stablish the corresponding comparisons.

Results

A total of 35 patients presented ANCA or anti-MBG for the first time during 2021, being this number of 15 during 2019. While in 2019, 73.3% of the patients presented anti-MPO antibodies and only 13.3% presented anti-PR3 antibodies, in 2021, 45.7% and 42.9% presented anti-MPO and anti-PR3 antibodies, respectively. Despite the important increase in the prevalence of anti-PR3 antibodies no significant differences were observed between both years (p=0.09). 27 out of 35 patients (77.1%) developed ANCA after receiving SARS-CoV-2 vaccine, being in the 88.6% of the cases BNT162b2 vaccine.

Conclusions

An increase in the development of ANCA has been observed during 2021 in comparison with 2019 which could be due to the administration of SARS-CoV-2 vaccine.