Guillain-Barré Syndrome Reported in Active, Placebo Groups of COVID Vaccine Trial

Anthony A. Amato, MD

A case report published in a recent online issue of Neurology has demonstrated 1 case of an individual involved in a COVID-19 vaccine trial developing Guillain-Barré syndrome (GBS), reporting on 1 such instance in the vaccine group. An additional 1 individual also developed GSB in the placebo group of the trial in question, for the Johnson & Johnson vaccine.¹

The vaccine arm patient did not report any clinical features that differentiated from typical GBS, nor is it possible to draw causal inferences about the relationship between COVID-19 vaccination and GBS. Importantly, the investigators noted that in order to avoid misattribution of adverse events (AEs) to the vaccine and to clarify the GBS risk, large-scale epidemiological studies and meta-analyses of data from monitoring systems are needed.

The authors, including Anthony A. Amato, MD, professor of neurology, Harvard Medical School; vice-chairman, Department of Neurology, and director, Neuromuscular Division and Clinical Neurophysiology Laboratory, Brigham and Women’s Hospital, concluded that although 1 of these instances of GBS occurred in the vaccine group, it does not prove the vaccine to be the cause of the autoimmune disorder.

“COVID-19 vaccines currently being administered in the United States have been shown to be safe and effective at reducing [the] risk of severe illness and death and are saving lives,” Amato said in a statement.² “With approximately 1 billion people worldwide expected to be vaccinated against COVID-19, we anticipate there could be thousands of cases of GBS that will occur around the time of the vaccination only by coincidence.”

“Our paper provides details of 1 case of the syndrome in someone who received the vaccine in the same trial where one person receiving a placebo also developed the syndrome, a fact that strengthens the possibility that the case in our report may have been a coincidence," Amato added.

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The report detailed the instance of a 60-year-old woman with a history of migraine enrolled in the trial who received the vaccine in December 2020. At the time the trial started, she was free of COVID-19 antibodies, and respiratory and gastrointestinal illness. Ten days after receiving the vaccine, she developed pain in the back and legs and was eventually unable to move either, with a study visit 4 days after symptom onset, on December 24, confirming a negative PCR assay for COVID-19.

The day after, she awoke with headache, nausea, vomiting, and diplopia and was admitted to the hospital, at which time she received a neurological examination and overnight treatment for migraine. Headache and diplopia persisted after discharge and she was readmitted on December 27. That examination revealed left eye esotropia on midline gaze and bilateral ocular abduction deficits but normal limb strength, sensation, and reflexes. Symptoms progressed to bilateral facial weakness and numbness the next day, accompanied by areflexia and 2/5 weakness of both legs. MRI and lumbar puncture, along with needle electromyography and electrophysiologic studies were conducted (FIGURE).

FIGURE. Guillain-Barré Syndrome in COVID-19 Vaccine Trial

She was treated with intravenous immunoglobulin 2g/kg over 2 days starting on December 29, 2020, after which her strength slowly improved. She was discharged to rehabilitation 10 days after admission.

“As the world manages the momentous task of vaccinating people across the globe, it is important to closely monitor any possible side effects and conduct large studies to determine if cases of GBS timed near vaccination are occurring by coincidence at the same rate that already occurs in the general population, or if the risk of GBS for COVID-19 vaccines is similar to or different from the small risk with vaccines like the flu vaccine,” Amato said. “Such monitoring will also help avoid incorrectly attributing side effects that are not scientifically linked to the vaccine. Based on experience with other vaccination initiatives and the data in the adverse monitoring systems of the COVID-19 vaccines gathered so far, we are certain that the benefits of vaccination outweigh the risks of COVID-19 infection.”

REFERENCES
1. Loza AMM, 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. Neurology. Published April 6, 2021. doi: 10.1212/WNL.0000000000011881
2. COVID-19 Trial: One Case of Guillain-Barré After Vaccine, But Also One After Placebo. News release. April 6, 2021. Accessed April 7, 2021. https://www.aan.com/PressRoom/Home/PressRelease/4878