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COVID vaccines linked to many serious health-related issues

The Global Vaccine Data Network (GVDN) recently conducted a comprehensive evaluation of 13 neurological, blood, and heart-related medical conditions to determine if there is an increased risk following COVID-19 vaccination

The research, hosted at the University of Auckland, is part of the Global COVID Vaccine Safety Project. The experts analyzed a vast dataset covering 99 million individuals across eight countries. Overall, the data encompassed more than 23 million person-years of follow-up.

Study significance 

“As of November 2023, at least 70.5% of the world’s population had received at least one dose of a COVID-19 vaccine,” wrote the researchers.

“This unparalleled scenario underscores the pressing need for comprehensive vaccine safety monitoring as very rare adverse events associated with COVID-19 vaccines may only come to light after administration to millions of individuals.”

Critical new insights into COVID vaccines

The research pinpointed pre-established safety signals for myocarditis and pericarditis after mRNA vaccines. In addition, the experts identified safety signals for Guillain-Barré syndrome alongside cerebral venous sinus thrombosis post-viral vector vaccines. 

The team also identified possible safety signals for transverse myelitis following viral vector vaccines and acute disseminated encephalomyelitis after both viral vector and mRNA vaccines.

A detailed follow-up of these findings was carried out by the GVDN’s site in Victoria, Australia, with the outcomes and data accessible on GVDN’s interactive data dashboards for public scrutiny.

Identifying vaccine safety signals 

The methodology used for the study was an observed versus expected rates analysis. This type of evaluation is valuable for spotting potential vaccine safety signals. It scrutinizes the risk of developing a medical condition post-vaccination against a timeframe prior to the vaccine’s availability.

Study lead author Kristýna Faksová is an expert in the Department of Epidemiology Research at Statens Serum Institut in Copenhagen, Denmark.

“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,” explained Faksová.

Broader implications of COVID vaccines

The initiative emphasizes transparency and effective communication with both the healthcare sector and the general public by making these data dashboards widely available. 

“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,” said GVDN Co-Director Dr. Steven Black.

“By making the data dashboards publicly available, we are able to support greater transparency, and stronger communications to the health sector and public,” added GVDN Co-Director Dr. Helen Petousis-Harris.

Further research is needed

The GCoVS Project is supported by the Centers for Disease Control and Prevention (CDC). The project enables the comparison of vaccine safety across a wide range of global populations. This highlights its significance in the broader context of vaccine research and public health.

“While our study confirmed previously identified rare safety signals following COVID-19 vaccination and contributed evidence on several other important outcomes, further investigation is warranted to confirm associations and assess clinical significance,” concluded the study authors. 

COVID vaccines 

Covid vaccines represent a monumental effort in the history of medicine. Researchers around the world quickly identified the genetic makeup of the virus, laying the groundwork for vaccine development. 

Next, companies and academic institutions rapidly developed and tested vaccine candidates through unprecedented collaboration.

Various technologies 

The most notable COVID vaccines, such as those developed by Pfizer-BioNTech and Moderna, employ various technologies. These vaccines use mRNA technology, which instructs cells to produce a protein that triggers an immune response

AstraZeneca-Oxford and Johnson & Johnson, on the other hand, use viral vector technology. This involves a harmless virus delivering genetic material from SARS-CoV-2 to stimulate the body’s immune defense.

Massive campaigns

Regulatory agencies across the globe conducted rigorous reviews to ensure the vaccines’ safety and efficacy before granting emergency use authorizations. Following approval, governments and health organizations launched massive vaccination campaigns to distribute doses worldwide.

The study is published in the journal Vaccine.


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