A paper that has just been published examined the potential risks of Guillain-Barré syndrome, an autoimmune neurological disorder, following COVID vaccines and SARS-CoV-2 infection.

Unsurprisingly, anti-vaxxers have jumped on this study to claim that COVID vaccines cause Guillain-Barré syndrome. The study has much more complicated results than the anti-vaxxer claims.

This article will examine what Guillain-Barré syndrome is and what the new study says about it and COVID vaccines.

What is Guillain-Barré syndrome?

Guillain-Barré syndrome (GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. 

The initial symptoms usually develop between a few hours to a few weeks and include weakness or a tingling feeling in your legs. The feeling can spread to your upper body. In severe cases, the patient can become almost paralyzed. This is life-threatening.

The cause of GBS is unknown, although the underlying mechanism involves an autoimmune disorder in which the body’s immune system mistakenly attacks the peripheral nerves. Sometimes, GBS appears to be triggered by an infection, although it can also be triggered by surgery and, very rarely, vaccination.

Guillain-Barré syndrome can be treated with intravenous immunoglobulins or plasmapheresis, with a good chance of full recovery in the majority of individuals. However, recovery may take weeks to years, although approximately one-third suffer some permanent weakness. Approximately 7.5% of those affected by GBS will die.

Just to be clear, Guillain-Barré syndrome is rare, with only one or two cases per 100,000 people annually.

COVID vaccines and Guillain-Barré syndrome study

In a paper to be published on 11 July 2025 in the peer-reviewed journal Vaccine, Jeffrey C Kowng, MD, MPH, ICES, Toronto, Ontario, Canada, and colleagues examined whether there was an association between GBS and certain COVID vaccines, along with the risk after SARS-CoV-2 infection.

They conducted a self-controlled case series study from 1 December 2020 to 9 August 2023 at 20 global sites within the Global Vaccine Data Network.

The researchers estimated the relative incidence (RI) of GBS within 1–42 days following receipt of adenoviral vector, mRNA, or inactivated COVID vaccines or SARS-CoV-2 infection.

Here are the key results:

• The researchers observed a 310% increased risk of GBS after receiving the adenoviral vector vaccine, Vaxzevria/Covishield, from Oxford-AstraZeneca.
• There was a 52% decreased risk of GBS after receiving the mRNA vaccine Comirnaty from Pfizer and BioNTech.
• There was a 335% increased risk of GBS after SARS-CoV-2 infection.

Summary

This study confirmed previous studies that showed that the adenoviral vector vaccines increased the risk of GBS, but less than the risk of GBS from a COVID infection itself, and that the mRNA vaccine decreased that risk.

If anyone pushes the claim that the mRNA COVID vaccines, from Moderna or Pfizer-BioNTech, cause Guillain-Barré syndrome, they are incorrect and deceptive. These mRNA vaccines actually reduce the risk of GBS, especially compared to the risk from COVID itself.

Frankly, I do not understand why anyone would take the risk of contracting COVID and refuse the vaccine. I guess I could ask that question of just about any vaccine.

Citations

• Nasreen S, Jiang Y, Lu H, Lee A, Cutland CL, Gentile A, Giglio N, Macartney K, Deng L, Liu B, Sonneveld N, Bellamy K, Clothier HJ, Sepulveda Kattan G, Naus M, Naveed Z, Janjua NZ, Nguyen L, Hviid A, Poukka E, Perälä J, Leino T, Chandra LA, Thobari JA, Park BJ, Choi NK, Jeong NY, Madhi SA, Villalobos F, Solórzano M, Bissacco CA, Carreras-Martínez JJ, Correcher-Martínez E, Urchueguía-Fornes A, Roy D, Yeomans A, Aurelius T, Morton K, Di Mauro G, Sturkenboom MC, Sejvar JJ, Top KA, Batty K, Ghebreab L, Griffin JB, Petousis-Harris H, Buttery J, Black S, Kwong JC. Risk of Guillain-Barré syndrome after COVID-19 vaccination or SARS-CoV-2 infection: A multinational self-controlled case series study. Vaccine. 2025 Jul 11;60:127291. doi: 10.1016/j.vaccine.2025.127291. Epub 2025 May 28. PMID: 40440921.
• Sejvar JJ, Baughman AL, Wise M, Morgan OW. Population incidence of Guillain-Barré syndrome: a systematic review and meta-analysis. Neuroepidemiology. 2011;36(2):123-33. doi: 10.1159/000324710. Epub 2011 Mar 21. PMID: 21422765; PMCID: PMC5703046.

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