Reports of Guillain-Barré Syndrome After COVID-19 Vaccination in the United States

"Discussion: In this retrospective cohort study, we identified 295 verified GBS cases among VAERS reports submitted from December 2020 through January 2022. GBS reporting after Ad26.COV2.S vaccination [Janssen] was approximately 9 to 12 times more common than after BNT162b2 or mRNA-1273 vaccination within 21- and 42-day postvaccination intervals. Similarly, observed GBS cases after Ad26.COV2.S vaccination were 2 to 3 times greater than expected based on background rates within 21- and 42-day postvaccination intervals ...

Our results include almost 300 reports of verified GBS cases in VAERS over a 14-month period and therefore may provide a more precise estimate of the relative risk of GBS after Ad26.COV2.S vaccination.

Of 10 deaths reported among individuals aged 57 through 88 years, GBS was the documented cause of death after medical record and death certificate review for 7 individuals ...

Ad26.COV2.S is a recombinant vaccine that uses a nonreplicating adenovirus vector encoding the SARS-CoV-2 spike protein to trigger an immunologic antibody response. It is theoretically possible that antibodies induced by Ad26.COV2.S vaccine may cross-react with glycoproteins on the myelin sheath of the axons of peripheral nerves, resulting in GBS. An increased risk of GBS after ChAdOx1 nCov-19 COVID-19 vaccination (AstraZeneca) has also been reported. This vaccine uses a replication-incompetent chimpanzee adenovirus vector and has been widely administered in Europe. In 1 study, the number of GBS cases within 14 days of ChAdOx1 nCov-19 vaccination was 1.4- to 10-fold greater than expected. Increased risk of GBS after these vaccines may suggest an adenovirus vector vaccine class association, at least with respect to COVID-19 vaccines. This possibility merits further evaluation and research concerning plausible mechanisms."