The AstraZeneca vaccine may increase the risk of the serious neurological condition Guillain-Barré syndrome (GBS) with the jab’s Trojan horse delivery system possibly to blame, scientists believe, in a discovery that may apply to similar vaccines. GBS is a rare condition that causes muscle numbness and pain, and can hinder movement, walking, swallowing and even breathing.
t is commonly caused by the gastroenteritis bug Campylobacter, which has a surface coating that appears to be human and so can trigger the body to attack its own nerves instead of invading germs, leading to GBS.
Scientists at University College London (UCL) have found a rise in cases of GBS in the first two to four weeks after receiving the AstraZeneca vaccine, but not other jabs, such as Pfizer or Moderna. Like many vaccines, the Astra jab uses a weakened chimp adenovirus to deliver the coronavirus spike protein into the body, and scientists have speculated that a reaction to adenovirus may be responsible for the rise in cases.
Adenovirus usually causes the common cold, but scientists believe it may also mimic human cells in a similar way to Campylobacter, confusing the immune system into attacking the body.
Professor Michael Lunn, the lead author, said: “At the moment, we don’t know why a vaccine may cause these very small rises in GBS. It may be that a non-specific immune activation in susceptible individuals occurs, but if that were the case similar risks might apply to all vaccine types. It is therefore logical to suggest that the simian adenovirus vector, often used to develop vaccines, including AstraZeneca’s, may account for the increased risk.”
Adenovirus-based jabs are used against a wide variety of pathogens, including tuberculosis, HIV and malaria.
GBS affects about 100 to 120 people in Ireland each year, and 1,500 people in the UK. Around 30 to 40pc of cases have no known causes, leading researchers to suspect that adenovirus could be a factor.
During the 1976 swine flu vaccination campaign in the United States, there was a small increase in GBS associated with the flu jab at that time, leading scientists to question whether the Covid vaccines could have a similar effect.
To find out, UCL researchers carried out a population-based study of NHS data in England to track GBS case rates against vaccination rollout.
Between January and October last year, 996 GBS cases were recorded in the UK National Immunoglobulin Database, but there was an unusual spike in GBS reports between March and April. For these two months there were about 140 cases per month compared with historical rates of about 100 per month.
Analysis showed 198 GBS cases (20pc) occurred within six weeks of the first vaccination dose in England. Overall, following a first dose of the AstraZeneca jab there were 5.8 excess GBS cases per million doses of vaccine, equating to an absolute total excess between January and July of between 98 and 140 cases. The rate is still significantly lower than the one in 1,000 rate of GBS associated with Campylobacter.
Recent data from the US also suggest the Johnson & Johnson vaccine, Janssen — which also uses an adenovirus entry system — raises the risk of GBS to similar levels as the AstraZeneca jab.
The research was published in the journal Brain.
An AstraZeneca spokesman said: “Guillain-Barré syndrome has been reported very rarely following vaccination with Vaxzevria [the company’s Covid jab]. Vaccination of any kind is a known risk factor for GBS and it is noted in the manuscript that the small number of GBS cases appears similar to increases previously seen in other mass vaccination campaigns.
“The EMA [European Medicines Agency], and other international bodies including the WHO, have all stated that the benefits of vaccination continue to outweigh any potential risks.”
Telegraph Group Media Ltd (2022)
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