No Credible Evidence COVID-19 mRNA Vaccines ‘Dramatically Increase’ Heart Attack Risk, Contrary to Flawed Abstract

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SciCheck Digest

The COVID-19 vaccines administered in the U.S. are not known to increase the risk of heart attack. But social media posts are misinterpreting an abstract in an American Heart Association journal as proof that the vaccine kills. The publisher later issued an “expression of concern” about the abstract “until a suitable correction can be published.” 

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Hundreds of millions of doses of COVID-19 vaccines have now been administered in the U.S. None of the vaccines authorized or approved for use in the U.S. are known to increase the risk of heart attack in any population. 

Rare cases of heart inflammation have been reported, primarily in young men, after receipt of the Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines. But studies have shown the risk is very low and most people recover quickly. The Centers for Disease Control and Prevention says the benefits of the vaccine outweigh the potential risks of heart inflammation. 

COVID-19, on the other hand, is known to be able to cause heart damage. Some research also suggests that the disease raises the risk of a heart attack and other related cardiovascular events.

A study published in the Lancet, for example, which included nearly 90,000 COVID-19 patients in Sweden and compared them with similar patients who did not have the disease, found that having COVID-19 was associated with more than triple the risk of having a first-time heart attack in the first two weeks after falling ill. The study also identified COVID-19 as a possible risk factor for ischemic stroke.

Yet, several online and social media posts claim mRNA COVID-19 vaccines “dramatically increase” heart attack risk, based on a misrepresented abstract published in the American Heart Association’s journal Circulation on Nov. 8. 

The abstract, which by nature is a brief summary and in this case represented preliminary research that is not peer-reviewed, concludes that “mRNA vacs dramatically increase inflammation on the endothelium and T cell infiltration of cardiac muscle and may account for the observations of increased thrombosis, cardiomyopathy, and other vascular events following vaccination.” The abstract is not part of a full scientific paper, and was presented as a poster at AHA’s Scientific Sessions online program on Nov. 13. None of the mRNA COVID-19 vaccines have been linked to thrombosis. 

After its publication, AHA was notified about “potential errors” in the abstract, and on Nov. 24, the journal published an ‘expression of concern’ stating it “may not reliable.”

“Specifically, there are several typographical errors, there is no data in the abstract regarding myocardial T-cell infiltration, there are no statistical analyses for significance provided, and the author is not clear that only anecdotal data was used,” the expression of concern says.

Statistical analyses are used by scientists to evaluate the likelihood that a particular result is due to chance or not. In other words, the abstract offered no way to tell if the purported changes following vaccination were actually so different as to not be just a fluke.

The author of the abstract, Dr. Steven R. Gundry, used a cardiac test to calculate the heart attack risk, but the co-developer of the test told that the test results have been misinterpreted. (More on that later.)

Gundry is a former cardiac surgeon who has attracted critical media attention for creating and promoting a controversial diet that claims lectins, a kind of protein found in most plants, can cause weight gain, inflammation and a set of other health issues. His lectin-free diet has been criticized for its lack of scientific evidence and his association with Gwyneth Paltrow’s Goop company, which has been accused of spreading dubious health and wellness advice, has also been a source of disapproval. In 2017, his diet was labelled as “the latest pseudoscience diet fad” and the “next gluten. He did not reply to our request for comment.

A spokesperson for AHA told the journal has been in communication with Gundry and that it gave him until the evening of Dec. 3 to provide corrections and an updated abstract. Gundry has submitted a corrected abstract “as part of the back and forth process,” but it has not been finalized or approved, the spokesperson said.

“Until the updated abstract is approved and published the expression of concern will remain in place,” AHA’s Suzanne Grant wrote in an email to

But by now the abstract’s conclusions have been widely shared by vaccine opponents, who have mostly disregarded the scientific concerns and presented Gundry’s words as “Proof the Covid Jab is Murder.” According to the article’s metrics as of Dec. 13, the abstract has been cited in 104,417 tweets by 63,079 Twitter users. 

A clip of British cardiologist Dr. Aseem Malhotra commenting on the abstract and linking the vaccines to heart attacks also went viral, and was later fact-checked by our colleagues at Full Fact and Reuters

And a video posted on Nov. 25 by John Campbell, a British retired nurse and science educator who has amassed a strong YouTube following during the pandemic, has received over 2 million views. In the video, Dr. Campbell, who has a doctorate in nursing education but is not a physician, reads the abstract and says that if the findings are correct, it would be “incredibly significant.” But are they? He’s not so sure.

Even though Campbell doesn’t mention the expression of concern, he says he’s surprised by the abstract typos, lack of clear data and methodology, and even by the fact that Gundry sells groceries on his website. “I must have worked with about 20 or 30 cardiologists over my career, and I can’t remember any having a grocery facility,” he says 20 minutes into the video.

But opponents of the vaccine have used the video as confirmation that the mRNA vaccines are going to provoke “a massive unimaginable amount of extra heart attacks.”

Dr. Douglas S. Harrington, a pathologist, is the chairman of Predictive Health Diagnostic Company, which owns the cardiac test used by Gundry, called the PULS Cardiac Test. He told us the numbers in the abstract are being misused by vaccine opponents. 

A woman shortly after receiving her COVID-19 vaccine. By FG Trade via Getty.

“It is not proof that people should not get vaccines. What it should be interpreted as is proof that the vaccine works,” he told us in an interview. “The best course of action for people is still to get vaccinated. And the real risk is in people who get COVID because of the intensity of the inflammatory response is significantly higher, than induced by the vaccine.”

AHA’s Grant said statements and conclusions of research presented at the association’s meetings or journals “are solely those of the study authors and do not necessarily reflect the Association’s policy or position.” The abstracts presented in a meeting are “intended to prompt scientific discourse” and the programming is not intended “to evaluate scientific validity.” Nonetheless, she said AHA is “reviewing its existing abstract submission processes.”

“The Association regrets any confusion regarding the Association’s position on COVID-19 vaccine, especially among the lay public who may be unfamiliar with scientific meetings. The American Heart Association itself has been unequivocal in its belief in and support of vaccination as the best available public health strategy to address the pandemic. The American Heart Association continues to fully support the CDC’s COVID-19 vaccination recommendations,” she wrote.

The PULS Cardiac Test

Gundry’s controversial abstract summarizes the results of a test that claims to be able to predict a patient’s five-year risk of suffering an Acute Coronary Syndrome, or what AHA defines as an “umbrella term for situations where the blood supplied to the heart muscle is suddenly blocked,” such as a heart attack. 

The PULS (Protein Unstable Lesion Signature) Cardiac Test (misspelled once in the abstract as PLUS Cardiac Test) is a blood test that its makers say can identify endothelial damage by measuring nine protein biomarkers: hepatocyte growth factor, eotaxin, monocyte-specific chemokine 3, cutaneous T-cell-attracting chemokine, interleukin 16, Fas ligand, soluble Fas, HDL, and HbA1c. 

Measurements of these biomarkers above the norm create a higher “PULS score,” and measurements below the norm lowers create a lower score. The score are categorized into risk categories: normal, borderline or elevated.  

Is it worth mentioning that none of the experts reached for this story were familiar with the PULS test, which has been questioned by experts online after Gundry’s abstract was published. According to a press release, as of June, the company had sold 120,000 tests since its launching in 2018.

Gundry’s preliminary research compared scores from 566 patients, aged 28 to 97, with an equal mix of males and females. It says measurements were taken three to five months before the administration of mRNA COVID-19 vaccines and then two to 10 weeks after a second dose. There is no detail on whether the patients had any other health conditions or previous heart issues. The abstract says measurements for three of the nine biomarkers — IL-16, sFas and HGF — increased.

“These changes resulted in an increase of the PULS score from 11% 5 yr ACS risk to 25% 5 yr ACS risk. At the time of this report, these changes persist for at least 2.5 months post second dose of vac,” the abstract reads.

Dr. Luigi Adamo, the director for cardiac immunology in the Johns Hopkins University Division of Cardiology who studies the relationship between the immune system and cardiac function, told he had not heard about the PULS cardiac test before, but he looked it up on our request.

“This test estimates the risk of having clinically significant coronary artery disease using a combination of clinical variables such as age and sex and serum levels of biomarkers that are associated with inflammation and/or atherosclerosis. Chronic elevation in non-specific markers of inflammation such as C reactive protein has been associated with an increased risk of heart attacks and therefore, conceptually, this makes sense to me,” Adamo told us in an email.

However, he said he did not understand its use to assess heart disease risk in people who have received an mRNA COVID-19 vaccine. 

“Vaccination is designed to induce a controlled inflammatory response with the goal of preparing the body to ‘fight’ the targeted pathogen. It is therefore expected that administration of a vaccine induces a transient increase in inflammatory mediators in the serum. However, this cannot be automatically interpreted as an increase in the risk of having a heart attack. Even if the mRNA vaccines caused a sustained elevation of specific serum biomarkers of inflammation, the prognostic value of this change in terms of risk of heart attacks would need to be validated with population data,” Adamo wrote.

Harrington, the test co-developer, agreed. He said all vaccines induce that kind of response and that the results of the test in this situation are not something to be concerned about.

“It should not be surprising to anyone that a vaccine temporarily stimulates a transient inflammatory response, which the PULS test is sensitive enough to capture. But does that mean that those people are at risk, or you shouldn’t get vaccinated? Absolutely not,” he said. 

The Abstract

Gundry’s abstract has been criticized by many for its sloppiness and lack of details. 

Johns Hopkins’ Adamo told us that even though by definition abstracts provide very little information, this one stands out “because it provides almost no information to support some very bold conclusions.” He added, “Its conclusions overall appear unsubstantiated.” 

Jeffrey Morris, director of the division of biostatistics at the University of Pennsylvania, said the limitations in the abstract, such as “the lack of details on the patient selection, analysis approach, and other details,” make it “impossible to evaluate.”  

“It appears the sample is a selective sample taken from a clinical practice,” Morris wrote. “Without knowledge of what subset were sampled/not sampled and their demographics, and what procedure was used to select these samples for processing, we cannot rule out the results driven by selection bias.”

The numbers in the abstract, he added, are impossible to understand. For example, in the results presented for the protein biomarker changes, Gundry uses symbols such as “=/-“ or “+/- ” without any context or explanation. Morris says it’s not clear whether the numbers are means, standard deviations, standard errors or a range of values. “And they don’t provide any statistical test to see whether the difference is statistically significant,” Morris said. 

Gundry has been criticized in the past for using an abstract for a poster presentation as if it contained peer-reviewed, validated findings. There is no evidence that he’s doing that now, as there are no references to this research on any of his website or social media platforms. But there is evidence that the abstract is flawed and being misrepresented by others to claim that vaccines cause heart attacks.

Clarification, Dec. 16: Grant, a spokesperson for the AHA, clarified that Gundry has submitted a corrected abstract, but it has yet to be approved. “We received them and as part of the back and forth process – yet they are not final until accepted/published,” she said.  

Editor’s note: SciCheck’s COVID-19/Vaccination Project is made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over’s editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation. The goal of the project is to increase exposure to accurate information about COVID-19 and vaccines, while decreasing the impact of misinformation.


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