Millions of people around the world have already received several doses of the vaccines against COVID-19 and this has reduced the severity of the symptoms of the disease in the vast majority of those who have been infected with SARS-CoV. -2 after vaccination. Although adverse effects associated with these vaccines have been reported, experts say that getting vaccinated is still the best option because the percentage of those affected is minimal and coronavirus infection can have serious health consequences, such as persistent COVID.
New research by scientists at University College London (UCL) published in Brain has identified a correlation between a first dose of AstraZeneca’s vaccine and a small but significant increase in cases of Guillain-Barré syndrome ( GBS), a serious autoimmune condition that affects the peripheral nervous system, often causing numbness, weakness, and pain in the extremities, and sometimes paralysis of breathing. GBS often occurs after suffering some type of infection, especially Camplylobacter infection.
The increase in Guillain-Barré cases did not occur with other vaccines
The researchers analyzed data from England’s public health system, the NHS, to track Guillain-Barré syndrome case rates during the vaccination campaign and, as part of a separate study of surveillance data from UK hospitals. United Kingdom, they looked at the phenotypes (characteristics/symptoms) of registered GBS cases to see if there were any specific features of Guillain-Barré syndrome associated with the COVID-19 vaccine.
The first dose of Pfizer and Moderna and the second dose of any vaccine did not show an excess risk of Guillain-Barré syndrome
In the UK, Pfizer’s COVID vaccine (COMIRNATY® (Tozinameran)) was launched in December 2020, followed by AstraZeneca (ChAdOx1 nCoV-19) in January 2021, and Moderna (mRNA-1273) in April 2021 The researchers noted that between January and October 2021, 996 cases of GBS were recorded in the UK National Immunoglobulin Database, and an unusual increase in GBS reports occurred between March and April 2021. During these two months there were about 140 cases per month compared to historical rates of about 100 per month.
By linking Guillain-Barré syndrome onset dates to vaccination receipt data found in the National Immunization Management System in England for each individual, they found that 198 GBS cases (20% of 966) occurred in within six weeks of the first dose of the COVID vaccine in England, which equates to 0.618 cases per 100,000 vaccinations. Of these, 176 people had been vaccinated with AstraZeneca, 21 with Pfizer and 1 with Moderna. Only 23 cases of GBS were reported within six weeks of any second dose of vaccine.
Overall, following a first dose of AstraZeneca’s vaccine, there were 5.8 excess cases of Guillain-Barré syndrome per million doses of vaccine, equivalent to an absolute total excess between January and July 2021 of between 98 and 140 cases. The first dose of Pfizer and Moderna and the second dose of any vaccine did not show an excess risk of GBS.
Professor Michael Lunn (UCL Queen Square Institute of Neurology), lead author of the study said: “Increased numbers of GBS cases are seen in the two to four week period after vaccination. A peak of cases was observed around 24 days after the first dose.” “The first doses of the AstraZeneca vaccine account for most or all of this increase. A similar pattern is not seen with the other vaccines or after a second dose of any vaccine.”
The expert added: “At the moment we do not know why a vaccine can cause these very small increases in Guillain-Barré syndrome.” “It may be that nonspecific immune activation occurs in susceptible individuals, but if that were the case, similar risks could apply to all types of vaccines.” And he concludes: “Therefore, it is logical to suggest that the simian adenovirus vector, which is often used to develop vaccines, including AstraZeneca’s, may explain the increased risk.”
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