Background: Guillain-Barré syndrome is an immune-mediated acute inflammatory polyneuropathy that is associated with various triggers, including certain infections and vaccines. It has been suggested that both SARS-CoV2 infection and vaccination may be triggering factors for Guillain-Barré syndrome, but evidence remain equivocal. Here we conducted a population-based incidence study of Guillain-Barré syndrome spanning the three years immediately prior to and the two years during the pandemic. Methods: Cases were identified by searching a regional diagnostic database for the ICD-10 code for Guillain-Barré syndrome. Individuals who fulfilled the Brighton Criteria for Guillain-Barré syndrome were included. Information on clinical presentation, laboratory values, and vaccination status were retrieved from medical records. We calculated the incidence immediately prior to and during the pandemic. Results: The Guillain-Barré syndrome incidence rate was 1.35/100,000 person-years for the pre-pandemic period, and 0.66/100,000 person-years for the pandemic period (incidence rate ratio: 0.49; p = 0.003). Three cases were temporally associated with SARS-CoV2 infection, and one case each to the Astra Zeneca and Pfizer-BioTech COVID-19 vaccines. Conclusions: Our results show that the incidence of Guillain-Barré syndrome decreased during the pandemic. This is most likely due to decreased prevalence of triggering infections, due to social restrictions. Our findings do not support a causal relationship between Guillain-Barré syndrome and COVID-19.

The Author(s). Published by S. Karger AG, Basel