Researchers find no relationship between Covid-19 vaccines and various neurological events
Research does find evidence of an increased risk for unvaccinated people who become infected with SARS-CoV-2. A study carried out by the IDIAPJGol Real World Epidemiology group analyzes the connection between vaccines against Covid-19 and neurological disorders such as Bell's palsy, encephalomyelitis or Guillain-Barré syndrome without finding evidence of an association between the two.
The Covid-19 pandemic has caused more than 5.5 million deaths worldwide and the numbers continue to rise. A major global research effort led to the development and approval of new vaccines, and more than 9 billion doses have already been administered to date.
As with any medication, there is a potential for adverse side effects, and concerns have recently been raised about cases of immune-mediated neurological disorders following vaccination.
Reports of cases of Guillain-Barré Syndrome (GBS) after the administration of some vaccines against Covid-19 led the EMA (European Medicines Agency) to include GBS as a very rare side effect. Cases of Bell's palsy, encephalomyelitis, and transverse myelitis have also been reported after vaccination. Therefore, large-scale epidemiological studies are required to determine whether vaccination against COVID-19 increases risks above reference rates in the general population.
Analysis of more than 8 million vaccinated people
Talita Duarte-Salles, leader of the Real World Epidemiology research group at IDIAPJGol, in collaboration with the University of Oxford, led a large international team to search for any link. The study, published in the BMJ[go to the original article], used UK Primary Care Registries (CPRD) and Catalonia Primary Care with Linked Hospital Registries (SIDIAP) to explore the potential link between Covid-19 vaccines and SARS-CoV-2 infection with the risk of developing any of the neurological events mentioned (GBS, Bell's palsy, encephalomyelitis and transverse myelitis).
“We analyzed data from more than 8 million recipients of EMA-approved COVID-19 vaccines, including vaccines manufactured by Pfizer-BioNtech, Moderna, Oxford-AstraZeneca, and Janssen. The incidence rates of each of the neurological disorders studied were measured in the cohorts of vaccinated people and the cohorts of people infected with SARS-CoV-2 and compared with the "expected" rates of these conditions that are normally seen in the general population (according to data from more than 14 million people between 2017 and 2019)”, explains Berta Raventós, one of the first authors of the article.
“In this study we did not see an association between vaccines against Covid-19 and the appearance of the neurological disorders studied, but we did find an increased risk of Bell's palsy, encephalomyelitis and GBS in unvaccinated patients who had contracted Covid-19. . These results are important as they underlie the safety of vaccines that have been approved by the EMA, as well as highlight some of the many harmful effects of being infected with SARS-CoV-2 for those who they continue without being vaccinated”, added Talita Duarte-Salles.
