COVID vaccines from companies like Pfizer, Moderna and AstraZeneca have been linked to rare occurrences of heart, brain and blood disorders, according to the largest vaccine study to date.
Researchers from the Global Vaccine Data Network analyzed 99 million people who received jabs in eight countries and monitored for increases in 13 medical conditions, Bloomberg News reported.
The study, which was published in the journal Vaccine last week, found the vaccines were linked to a slight spike in neurological, blood and heart-related medical conditions.
Rare cases of myocarditis — inflammation of the heart muscle — were found in the first, second and third doses of Pfizer-BioNTech’s and Moderna’s mRNA vaccines.
Another heart condition, pericarditis, the inflammation of the cardiac muscle, had a 6.9-fold increased risk in those who received a third dose of AstraZeneca’s viral-vector shot, the study found.
Meanwhile, a first and fourth dose of Moderna’s jab had a 1.7-fold and 2.6-fold increased risk, respectively.
An increased risk also was identified of a type of blood clot in the brain from viral-vector shots such as the one developed by the University of Oxford and manufactured by AstraZeneca, Bloomberg said.
There was a 2.5 times greater risk of developing Guillain-Barre syndrome, a rare neurological disorder in which the immune system attacks the nerves, among people who received AstraZeneca’s jab, according to the study.
Possible safety signals for transverse myelitis, a spinal cord inflammation, were identified after viral-vector vaccines, as was acute disseminated encephalomyelitis, the inflammation and swelling in the brain and spinal cord, after both viral-vector and mRNA vaccines, the researchers found.
The experts at GVDV 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.
More than 13.5 billion doses have been administered worldwide since the start of the pandemic. A small proportion of those immunized were harmed by the shots, stoking debate about the benefits of the jabs versus the risks.
“The size of the population in this study increased the possibility of identifying rare potential vaccine safety signals,” lead author Kristýna Faksová of the Department of Epidemiology Research, Statens Serum Institut in Denmark, said in a release.
“Single sites or regions are unlikely to have a large enough population to detect very rare signals,” she added.
One expert who was not involved in the study maintained that the benefits of the vaccines outweigh the risks.
“The odds of all of these adverse events is still much, much higher when infected with SARS-CoV-2 (COVID-19), so getting vaccinated is still by far the safer choice,” Jacob Glanville, CEO of biotech company Centivax, told Forbes.
Dr. Marc Siegel, clinical professor of medicine at NYU Langone Medical Center, shared a similar conclusion.
“The massive study and review of the data reveals some rare association of the mRNA vaccines and myocarditis, especially after the second shot, as well as an association between the Oxford Astra Zeneca adenovirus vector vaccines and Guillain-Barre syndrome,” Siegel, who was not involved in the study, told Fox News Digital.
“But these risks are rare and other studies show that the vaccine decreases the risk of myocarditis from COVID itself dramatically,” he said, adding that all vaccines have side effects.
“It always comes down to a risk/benefit analysis of what you are more afraid of — the vaccine’s side effects or the virus itself, which can have long-term side effects in terms of brain fog, fatigue, cough, and also heart issues,” Siegel said.
“Denying or exaggerating a vaccine’s side effects is not good science — nor is underestimating the risks of the virus, especially in high-risk groups,” Siegel added.
Pfizer told The Post in a statement that while it “was not involved in this study, we welcome independent research and academic discourse to advance the study of COVID-19.
“Safety is a top concern for all of us and Pfizer and BioNTech take reports of side effects that are potentially associated with our COVID-19 vaccine very seriously,” it said in the email.
“Since its initial authorization for use in December 2020, the Pfizer-BioNTech COVID-19 vaccine has been administered to more than 1.5 billion people, has demonstrated a favorable safety profile in all age groups, and has helped protect against severe COVID-19 outcomes, including hospitalization and death,” the company added.
Moderna and AstraZeneca did not immediately respond to requests for comment.
