Is there a causal nexus between COVID-19 infection, COVID-19 vaccination, and Guillain-Barré syndrome?

Guillain-Barré syndrome (GBS) is an immune-mediated inflammatory polyradiculoneuropathy, which commonly leads to a very high level of neurological disability. Especially, after the global outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the causation between GBS and SARS-CoV-2 infection and the coronavirus disease 2019 (COVID-19) vaccination have aroused widespread concern. In the review, we analyzed the impacts of SARS-CoV-2 infection and COVID-19 vaccination on GBS globally, aiming to further understand the characteristics of GBS associated with COVID-19. Based on the electrophysiological data, patients suffering from GBS related to COVID-19 manifested as an acute inflammatory demyelinating polyneuropathy (AIDP). Moreover, we summarized the current findings, which may evidence GBS linking to SARS-CoV-2 infection and COVID-19 vaccination, and discussed the underlying mechanisms whether and how the SARS-CoV-2 virus and COVID-19 vaccination can induce GBS and its variants.