Greater Risk of Rare Neurological Symptoms From COVID-19 Than Vaccines: Study

Tim Locke

October 25, 2021

Coronavirus infection is linked with a greater risk of rare neurological complications than having a first vaccine dose with Oxford/AstraZeneca or Pfizer/BioNtech, according to research led by the University of Oxford.

The study in Nature Medicine is based on 32 million patient records from England.

Those having the Oxford/AstraZeneca vaccine had an increased risk of Bell's palsy and Guillain-Barré  syndrome in the 28 days after their first jab at an estimated rate of 38 excess cases per 10 million people vaccinated.

Those having Pfizer/BioNTech vaccine had an increased risk of haemorrhagic stroke over the same time period at a rate of 60 extra cases per 10 million people vaccinated.

In the same time period following a positive COVID-19 test, there was a substantially higher risk of encephalitis meningitis and myelitis, myasthenic disorders, and Guillain–Barré syndrome at rates of 123, 163, and 145 excess cases per 10 million people respectively.

Additional work was carried out on people who tested positive before vaccination in Scotland that did not change the overall results.

Independent Analysis

The co-lead authors stress they were fully independent from the developers of the Oxford vaccine.

Martina Patone, medical statistician, Nuffield Department of Primary Care Health Sciences, University of Oxford, said in a statement: "We found different risks for different types of neurological condition depending on which vaccine people received. However, these were substantially lower than the risks occurring in association with a positive COVID-19 PCR test. For example, we estimate 145 excess cases of Guillain-Barré  syndrome per 10 million people in the 28 days after a positive SARS-CoV-2 test, compared to 38 per 10 million for those who received the ChAdOx1nCoV-19 [Oxford] vaccine.”

Clinical Lecturer, Dr Lahiru Handunnetthi, said: "These neurological complications were very rare, but awareness of these will be important for patient care during mass vaccination programmes across the world."

Julia Hippisley-Cox, professor of clinical epidemiology and general practice at the University of Oxford, and co-author said: "We know the COVID-19 vaccines are very effective at reducing risks of severe outcomes from COVID-19 infection. Whilst there are some increased risks of very rare neurological complications associated with the Oxford/AstraZeneca vaccine, these are much smaller than the risks associated with COVID infection itself. However, these very rare conditions are very important to spot to ensure that clinicians know what to look for, aid earlier diagnosis, and inform clinical decision making and resource management."

Commenting via the Science Media Centre, Peter Openshaw, professor of experimental medicine, Imperial College London, said: "The authors report an association between the Pfizer vaccine and haemorrhagic stroke – but this was only seen in one cohort, it wasn’t also found in the Scottish data, and it looks to me a very small signal and possibly not very significant.

"The neurological complications of SARS-CoV-2 vaccines are much rarer than the neurological complications of COVID-19, showing the vital importance of getting vaccinated."

Neurological complications after first dose of COVID-19 vaccines and SARS-CoV-2 infection.Nature Medicine, 25 October 2021.


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