Health

Study of rare neurological events after COVID-19 vaccination


Some people have developed Guillain-Barr syndrome after receiving the Oxford-AstraZeneca or Pfizer-BioNTech vaccines, as the European Medicines Agency has listed Guillain-Barr syndrome as a rare side effect of these vaccines. – Please.

However, to date, research findings on the risk of Guillain-Barr syndrome and other immune-mediated neurological disorders following COVID-19 vaccination have been mixed.


To address this issue, researchers began studying the association between the COVID-19 vaccine, SARS-CoV-2 (the virus that causes COVID-19) and the risk of neurological events over immune mediators. Their findings are based on data from two large primary healthcare electronic record databases in the UK and Spain.

Of those, 8.3 million have received at least one dose of the COVID-19 vaccine (Oxford-AstraZeneca, Pfizer-BioNTech, Moderna, or Johnson & Johnson) and 735,870 unvaccinated people have tested positive for COVID- 19 positive.

More than 14.3 million people from the general population were also studied retrospectively (before the pandemic) to assess historical context rates. This group was unvaccinated and had no previous litter because neither was present at the time.

Special events for the research team were four immune-mediated neurological disorders: Bell’s palsy, myositis, Guillain-Barr syndrome, and transverse myelitis (inflammation of the spinal cord).

The incidence of these disorders was estimated between 21 days after the first dose of vaccine and 90 days after a positive test result, with background rates in the general population from 2017 to 2019.

Overall, the researchers found that post-vaccination rates matched the expected population (background) rates for Bell’s palsy, myositis, and Guillain-Barr syndrome. The incidence of transgenic myelitis was so rare (less than 5 cases in all vaccinated groups) that it could not be analyzed.

However, the proportion of these items was higher than expected after COVID-19 infection. This was an observational study, so no cause could be determined, and the researchers could not rule out the possibility that unknown differences between groups or incorrect classification of the disorder may have influenced the outcome. their fruit.

But some studies have shown an increased risk of immune-mediated neurological events after COVID-19 infection, and their results have been very good.

Therefore, they said: “We did not find any safety signal for any of the immune-mediated neurological events studied following vaccination against covid-19. However, infection with SARS- CoV-2 is associated with an increased risk of Bell’s palsy, encephalitis, and Guillain-Barr syndrome.”

More evidence is needed to understand the long-term adverse effects of COVID infection and vaccination, while larger groups are also needed to study the effects of vaccination on different age groups, mainly in young people, they added.

Importantly, all risks even those observed after contracting COVID-19 are completely small for an individual, the experts wrote in the linked editorial. However, they also note that even small absolute risks “can result in a significant burden on health care systems in the context of mass vaccination and widespread infection.”

It is the responsibility of researchers and clinicians to discuss these findings with affected patients and their families, and to acknowledge the uncertainty inherent in making assumptions at the level patients from demographic studies.

One approach that illustrates the good evidence from larger studies is that although neurological conditions are rare immediately after a COVID-19 vaccine, these conditions are not common in people who have already been vaccinated. vaccinated as unvaccinated people.

They conclude: “We can never say exactly what caused an individual to develop the neurological condition, but COVID-19 vaccination is a very unlikely reason for most people. “.

Source: Medindia



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