Researchers have identified rare but significant health issues related to the COVID-19 vaccine, including heart, blood, and neurological disorders. [Source]
The Global COVID Vaccine Safety (GCoVS) Project, using data from the Global Vaccine Data Network (GVDN) across eight countries involving more than 99 million individuals, has shed light on these concerns.
Kristýna Faksová, lead author of the study from the Department of Epidemiology Research at Statens Serum Institute in Copenhagen, explained the scale of the research, stating, “The size of the population in this study increased the possibility of identifying rare potential vaccine safety signals. Single sites or regions are unlikely to have a large enough population to detect very rare signals.”
This extensive approach has allowed for the detection of adverse events of special interest (AESI) including myocarditis, pericarditis, Guillain-Barré syndrome, and cerebral venous sinus thrombosis, associated with both mRNA vaccines like Pfizer/BioNTech and Moderna’s mRNA-1273, and adenovirus-vector vaccines like the Oxford/AstraZeneca ChAdOx1. [Source]
The study employed a meticulous “observed vs. expected” analysis, a critical method for the early detection of potential safety concerns.
Despite the identification of these risks, the researchers emphasize the rarity of such adverse events.
Guillain-Barré syndrome and cerebral venous sinus thrombosis were observed more frequently after the first dose of the ChAdOx1 vaccine, and acute disseminated encephalomyelitis, a swelling in the brain and spinal cord, was more common after the first dose of the mRNA-1273 vaccine.
Dr. Steven Black, co-director at GVDN, underscores the significance of global collaboration in vaccine safety monitoring, stating, “GVDN supports a coordinated global effort to assess vaccine safety and effectiveness so that vaccine questions can be addressed in a more rapid, efficient, and cost-effective manner. We have a number of studies underway to build upon our understanding of vaccines and how we understand vaccine safety using big data.”
This global study confirms known risks but also introduces new findings such as acute disseminated encephalomyelitis and transverse myelitis, linked to the AstraZeneca vaccine.
Prof Jim Buttery, co-director of the Global Vaccine Data Network, reflects on the importance of large-scale data analysis, “for rare side effects, we don’t learn about them until the vaccine has been used in millions of people.”
The comprehensive findings, published in the international journal Vaccine, underscore the critical balance of vaccine safety and efficacy.