Researchers have found a concerning association between COVID-19 infection and an increased risk of developing the rare disorder Guillain-Barré syndrome over the following six weeks. However, the study authors, working with the American Academy of Neurology, also note those who received the Pfizer-BioNTech mRNA vaccine showed a lower risk of developing Guillain-Barré syndrome in comparison to others who did not receive the vaccine.
Guillain-Barré syndrome is a rare autoimmune disorder that causes the immune system to attack nerve cells and portions of the peripheral nervous system. Symptoms usually begin with weakness in the hands and feet before eventually progressing to full-blown paralysis. While it can be life-threatening if left untreated, the majority of Guillain-Barré patients make a full recovery.
The exact cause of Guillain-Barr syndrome remains a mystery, but it often develops after gastrointestinal or respiratory infections. Researchers note the rare disorder develops in up to 20 out of every one million people annually, and cases following certain vaccinations are extremely rare.
“These findings further highlight the benefits of ongoing vaccination programs with mRNA-based vaccines,” says study author Anat Arbel, MD, of Lady Davis Carmel Medical Center in Haifa, Israel. “The results have important clinical and public health implications,” in a media release.
This project assessed over three million people living in Israel, all of whom had no previous history of Guillain-Barr. Researchers tracked participants starting from Jan. 1, 2021 until June 30, 2022. During that period, 76 individuals developed Guillain-Barr. The study authors then matched each Guillain-Barr patient to 10 people who did not have the syndrome (760 people in total).
Next, the research team assessed whether participants had a COVID infection or a COVID vaccine over the six weeks prior to being diagnosed with Guillain-Barré (or the same period among matched participants).
This approach led to the finding that those with a recent COVID infection were six times more likely to develop Guillain-Barré than others who had gone without an infection. In all, 12 percent of those with Guillain-Barré had a recent COVID infection, in comparison to just two percent of the people who did not have Guillain-Barré.
Additionally, 11 percent of Guillain-Barré patients had been recently vaccinated with an mRNA vaccine, in comparison to 18 percent of those who did not have Guillain-Barré. All in all, the study estimates people with a recent mRNA vaccination were over 50 percent less likely to develop Guillain-Barré than the unvaccinated.