Reader Response: Guillain-Barré Syndrome in the Placebo and Active Arms of a COVID-19 Vaccine Clinical Trial
JustinWiller, Attending Neurologist, Justin Willer MD PC
Submitted May 31, 2021
Caution is necessary, as vaccines may not have just one effect on the risk of Guillain-Barré Syndrome GBS but a dual effect. Vaccination reduces the risk of GBS by decreasing the risk of infection. On the other hand, vaccines also have a direct effect that increases the risk of GBS, by producing antibodies that cross-react with antigens of peripheral nerves.
The effect of decreasing infection has a much greater effect on the risk of GBS—for example, the risk reduction of GBS from decreasing infection due to the influenza vaccine is 9 times greater than its risk of causing GBS—so it is difficult to prove a causal relationship between vaccination and GBS by standard epidemiologic methods.
Disclosure
The author reports no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
Márquez Loza AM, Holroyd KB, Johnson SA, Pilgrim DM, Amato AA. Guillain- Barré Syndrome in the Placebo and Active Arms of a COVID-19 Vaccine Clinical Trial: Temporal Associations Do Not Imply Causality [published online ahead of print, 2021 Apr 6]. Neurology. 2021;10.1212/WNL.0000000000011881.
Caution is necessary, as vaccines may not have just one effect on the risk of Guillain-Barré Syndrome GBS but a dual effect. Vaccination reduces the risk of GBS by decreasing the risk of infection. On the other hand, vaccines also have a direct effect that increases the risk of GBS, by producing antibodies that cross-react with antigens of peripheral nerves.
The effect of decreasing infection has a much greater effect on the risk of GBS—for example, the risk reduction of GBS from decreasing infection due to the influenza vaccine is 9 times greater than its risk of causing GBS—so it is difficult to prove a causal relationship between vaccination and GBS by standard epidemiologic methods.
Disclosure
The author reports no relevant disclosures. Contact journal@neurology.org for full disclosures.
References