In “Guillain-Barré Syndrome in the Placebo and Active Arms of a COVID-19 Vaccine Clinical Trial,” Márquez Loza et al. presented a patient who developed the Guillain-Barré syndrome (GBS) after being vaccinated in a COVID-19 vaccine clinical trial and highlighted the fact that this should not be considered a postvaccination complication, given that, by chance alone, 900–2,200 people can be expected to develop GBS within 6 weeks of a 1-dose vaccine and 1,500–3,700 people can be expected to develop GBS within 10 weeks of a 2-dose vaccine. Willer comments that although vaccines can increase the risk of GBS because of antibody production, they can also decrease the risk of GBS because of infection prevention. On behalf of the authors, Amato agrees that vaccines can reduce the risk of postinfection GBS in general but notes that a large epidemiologic cohort study found no causal relationship between COVID-19 and GBS and no evidence of molecular mimicry between any SARS-CoV-2 proteins and axonal or myelin proteins in human nerves. Amato recommends performance of large-scale epidemiologic studies and meta-analyses to better understand the relationship between COVID-19 vaccination and GBS.