Guillain-Barré Syndrome after COVID-19 vaccination

Until October 12th 2022, the Netherlands Pharmacovigilance Centre Lareb received 72 reports of  Guillain-Barré Syndrome (GBS) following COVID-19 vaccination. GBS is labeled as a rare side effect of the COVID-19 vaccines of AstraZeneca and Janssen. Based on the reports, no conclusion can be made about a possible relationship between GBS and the Pfizer/BioNTech and Moderna COVID-19 vaccines.

Guillain-Barré syndrome (GBS) is a rare and severe neurological disorder where the immune system attacks and damages nerves outside the central nervous system. GBS often presents with progressive symmetrical muscle weakness with reduced and/or absent reflexes. The symptoms usually progress over a period of 2 weeks.

Lareb reports
In the majority of the reports GBS occurred within 6 weeks after vaccination. Of the reporters, 30 received the Pfizer/BioNTech vaccine (Comirnaty), 8 the Moderna vaccine (Spikevax), 18 the AstraZeneca vaccine (Vaxzevria) and 16 the Janssen vaccine (Jcovden). The Pfizer/BioNTech vaccine is the most used COVID-19 vaccine in the Netherlands. The fact that GBS occurred after vaccination does not always imply that the vaccine was the cause.

The total number of reports received is compared to the background incidence rates of GBS. For the AstraZeneca and Janssen vaccine, the number of reports was higher than expected based on the background incidence rates. For the Pfizer/BioNTech and Moderna vaccine, the number of reports did not exceed the background incidence rates of GBS.

The full overview of the reports can be found here.

The mechanism of GBS following vaccination is unknown
One hypothesis is that an autoimmune response to the antigen in the vaccine triggers the development of GBS. Other possible risk factors for GBS are infections or autoimmune disorders.