Incidence of Glomerulonephritis after SARS-CoV-2 mRNA Vaccination

Numerous cases of glomerulonephritis manifesting shortly after SARS-CoV-2 vaccination have been reported, but causality remains unproven. We studied the association between mRNA-based SARS-CoV-2 vaccination and new-onset glomerulonephritis using a nationwide retrospective cohort and case-cohort design. Data from all Swiss pathology institutes processing native kidney biopsies served to calculate incidence of IgA nephropathy, pauci-immune necrotizing glomerulonephritis, minimal change disease and membranous nephropathy. The observed incidence during the vaccination campaign (Jan to Aug 2021) was not different from the expected incidence based on the years 2015 to 2019 (incidence rate ratio 0.86, 95%-credible interval 0.73–1.02) and did not cross the upper boundary of the 95% credible interval for any month. Among 111 patients aged >18 years with newly diagnosed glomerulonephritis between January and August 2021, 38.7% had received at least one vaccine dose before biopsy, compared to 39.5% of the general Swiss population matched for age and calendar-time. The estimated risk ratio for the development of new-onset biopsy-proven glomerulonephritis was 0.97 (95% CI 0.66–1.42, P=0.95) in vaccinated vs. unvaccinated individuals. Patients with glomerulonephritis manifesting within 4 weeks after vaccine did not differ clinically from the rest of the cohort. Results were consistent across all types of glomerulonephritis with the possible exception of minimal change disease. In conclusion, vaccination against SARS-CoV-2 was not associated with new-onset glomerulonephritis in these two complementary studies. Most temporal associations between SARS-CoV-2 vaccination and glomerulonephritis are likely coincidental.