The largest vaccine study to date has found a slight increase in rare heart, brain, and blood disorders linked to COVID-19 vaccines from Pfizer, Moderna, and AstraZeneca. The study was conducted by researchers from the Global Vaccine Data Network (GVDN) who analyzed data from 99 million vaccinated individuals across eight countries, monitoring for 13 specific medical conditions.
The study, published in the Vaccine journal, found that the vaccines were associated with a minor increase in neurological, blood, and heart-related medical conditions. Among these were rare instances of myocarditis, an inflammation of the heart muscle, found in recipients of the first, second, and third doses of Pfizer-BioNTech’s and Moderna’s mRNA vaccines.
The study also found a 6.9-fold increased risk of pericarditis, an inflammation of the cardiac muscle, in those who received a third dose of AstraZeneca’s viral-vector shot. Additionally, the first and fourth doses of Moderna’s vaccine were associated with a 1.7-fold and 2.6-fold increased risk, respectively.
The research also identified an increased risk of a specific type of blood clot in the brain from viral-vector vaccines like the one developed by the University of Oxford and manufactured by AstraZeneca. A 2.5 times greater risk of developing Guillain-Barre syndrome, a rare neurological disorder where the immune system attacks the nerves, was found among people who received AstraZeneca’s vaccine.
The GVDN researchers in New Zealand, a research arm of the World Health Organization, examined 13 medical conditions that they considered “adverse events of special interest” among the subjects, aiming to identify higher-than-expected cases after a vaccine.
Despite these findings, experts maintain that the benefits of the vaccines outweigh the risks. Jacob Glanville, CEO of biotech company Centivaix, emphasized that the odds of these adverse events are still much higher when infected with SARS-CoV-2 (COVID-19), making vaccination the safer choice. Dr. Marc Siegel, clinical professor of medicine at NYU Langone Medical Center, echoed this sentiment, stating that while the vaccines do have side effects, they are rare and the vaccines significantly decrease the risk of severe COVID-19 outcomes.
Pfizer, in a statement to The Post, welcomed independent research and academic discourse to advance the study of COVID-19. The company emphasized that safety is a top concern and that they take reports of side effects potentially associated with their COVID-19 vaccine very seriously. Moderna and AstraZeneca did not immediately respond to requests for comment.