New warning for AstraZeneca COVID-19 vaccine

A warning about Guillain-Barré syndrome has been added to the prescribing information for Vaxzevria.

A causal link between COVID-19 vaccination and Guillain-Barré syndrome has not been proven. | GETTY IMAGES
A causal link between COVID-19 vaccination and Guillain-Barré syndrome has not been proven. | GETTY IMAGES

Guillain-Barré Syndrome (GBS) has been reported very rarely following vaccination with Vaxzevria, previously known as COVID-19 Vaccine AstraZeneca. Healthcare professionals should be alert to the signs and symptoms of GBS to ensure correct diagnosis, adequate supportive care and treatment, and to rule out other causes.

Further information

View Vaxzevria drug record

The MHRA says a causal link between COVID-19 vaccination and GBS has not been proven and cases of GBS that occur following vaccination may occur by chance, with a background rate of GBS of 2 per 100,000 per year.

People who have had GBS unrelated to COVID-19 vaccination or after their first COVID-19 vaccination should still be offered two doses of COVID-19 vaccine, the MHRA has confirmed. 

Muscle weakness

GBS typically presents with sensory abnormalities, muscle weakness and autonomic dysfunction, and is often triggered by infection. It usually develops over hours or days, starting in the extremities before spreading to the arms and legs, typically affecting both sides. Initial symptoms include numbness, pins and needles, muscle weakness, pain, and balance and coordination problems. Severity can range from mild, transient weakness to complete paralysis. 

Since all adults in the UK have been offered a COVID-19 vaccine, the MHRA says a certain number of cases of GBS would be expected following vaccination. GBS cases have been reported following other vaccination programmes, with much research focusing on GBS and the seasonal flu vaccine. The data has been variable from season-to-season, but if there has been an increased risk, it has been in the range of 1 to 2 additional GBS cases per million flu vaccine doses administered. The evidence also suggests that an individual is more likely to get GBS after having flu than after the vaccination.

As of 11th August 2021, in the UK there have been 383 reports of GBS following Vaxzevria vaccination and 23 reports of Miller Fisher syndrome, a variant of GBS which causes abnormal muscle coordination, paralysis of eye muscles and loss of tendon reflexes. There were 42 reports of GBS following Comirnaty (Pfizer/BioNTech) vaccination and 2 following Spikevax (Moderna) vaccination. Over this time period, 24.8 million first doses and 23.9 million second doses of Vaxzevria have been administered, 21.0 million first doses and 24.7 second doses of Comirnaty have been administered, and 1.4 million first doses and 0.6 million second doses of Spikevax.

The MHRA says that cases of GBS following vaccination with Comirnaty or Spikevax are less than the number expected to occur by chance, and the rare occurrence rates following Vaxzevria vaccination are 'broadly consistent with reports from previous viral mass vaccination campaigns'.

The European Medicine Agency recommended the addition of a warning to raise awareness of GBS following vaccination with Vaxzevria, with 227 GBS cases reported by 27 June 2021 and 51.4 million doses given by 20 June 2021. 

The World Health Organization has also reviewed the data, concluding that the potential benefits of Vaxzevria continue to outweigh any potential risk of GBS.

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