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An electron microscopy image of a cell infected by the coronavirus that causes COVID-19.
What are breakthrough infections?

Covid-19 infection may occasionally trigger Guillain-Barré syndrome, a rare but potentially serious neurological condition, according to new research appearing in the journal Brain, and published by Oxford University Press.

Guillain-Barré syndrome is an autoimmune neurological disorder where the body's immune system begins to attack the body itself and damage nerve cells. It can cause muscle weakness and occasionally paralysis.

The disease is relatively rare - in the US, 3000-6000 people develop the condition every year. However, it can be severe and last for weeks or many years.

The precise cause is unknown although Johns Hopkins Medicine notes that it often develops after a respiratory or gastrointestinal viral infection.

According to the published paper, doctors have reported more than 90 Guillain-Barré diagnoses following a possible Covid infection since the beginning of the pandemic. However, the authors note that it is unclear if Covid is another potential trigger, or whether the reported cases are coincidental.

Study analysis

The research team used an international collection of Guillain-Barré syndrome patients, known as the International GBS Outcome Study (or IGOS), and studied these patients from January until May 2020. Around 49 patients were added to the study during this period - from China, Denmark, France, Greece, Italy, the Netherlands, Spain, Switzerland, and the UK.

The study found that 22% of the Guillain-Barré syndrome patients included during the first four months of the pandemic had a preceding Covid infection - and they were all over 50 years of age.

These patients frequently experienced facial palsy (64%), which is weakness of the facial muscles. Upon hospital admission, 73% of the Guillain-Barré patients with a Covid infection had increased inflammatory markers, and all of them fulfilled the diagnostic criteria for both Guillain-Barré syndrome and Covid infection.

Covid may precede GBS

Researchers stressed that they did not find more patients diagnosed with Guillain-Barré syndrome during the first four months of the pandemic compared to previous years. This means that while there wasn't a strong link between Covid infection and Guillain-Barré syndrome per se, a Covid infection could sometimes lead to patients developing the syndrome.

"Our study shows that Covid-19 may precede Guillain-Barré syndrome in rare cases,'' said co-author, Dr Bart Jacobs. He added: "But the existence of a true association or causal relation still needs to be established".

GBS and vaccination

The Covid-19 vaccine by Johnson & Johnson (J&J) has been linked to a small increase in the risk of Guillain-Barré syndrome, Health24 reported in July 2021.

In most of those cases, symptoms began within 42 days following receipt of the single-dose vaccine. Preliminary reports by the US Centers for Disease Control and Prevention (CDC) showed that out of 12.8 million J&J doses administered in the US, there had been only about 100 cases of the syndrome.

Comment: This number could be much higher since we know injection injury is massively under reported.

Results from South Africa's Sisonke study, where the vaccine was given to close to 500,000 healthcare workers, also indicated that one participant - a 40-year-old male - was diagnosed with Guillain Barré syndrome.

Co-principal investigator of the study and president of the SA Medical Research Council, Professor Glenda Gray told Health24: "The important thing is that if we had one case in [almost] half a million people, and it was resolved, it puts it into context. But it's also important for people to be aware of side effects so that they can then monitor it and get interventions early."

Symptoms and recovery

Symptoms of Guillain-Barré syndrome can include varying degrees of weakness or tingling in the legs, which, sometimes spreads to the arms and upper body, explains Johns Hopkins Medicine.

Symptoms generally pass within weeks but in some cases, they can increase in intensity until the muscles cannot be used at all and the person becomes almost totally paralysed. This then becomes life-threatening and is considered a medical emergency.

Partial recovery is possible from even the most severe cases of the disorder, although the person may always experience some degree of weakness.