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In the largest study to date on myocarditis deaths related to COVID-19 vaccination, researchers found that 100 people in England died of myocarditis soon after receiving a COVID-19 vaccine.

The study, published Aug. 22 in the American Heart Association’s journal, Circulation, found more than half (51) of the deaths occurred within 1 to 28 days after receiving a dose of the AstraZeneca vaccine and just under half (49) of the deaths occurred within 1 to 28 days after a dose of the Pfizer-BioNTech vaccine.

The AstraZeneca vaccine, not authorized for use in the U.S., uses an adenovirus technology similar to that used by Johnson & Johnson’s (J&J), or Janssen) COVID-19 vaccine, which is authorized for emergency use in the U.S.

Prior research has underscored the risk of fatal myocarditis associated with the mRNA technology used in the Pfizer and Moderna COVID-19 vaccines. This study showed the technology used in AstraZeneca’s vaccine poses a similar risk.

Dr. Peter McCullough, an internist and cardiologist in Dallas, Texas, in a Sept. 15 tweet highlighted the importance of the new study.

“This study confirms the risk of myocarditis extends to both mRNA vaccines and the adenovirus vaccines,” McCullough told The Defender.

The technology used in AstraZeneca and J&J viral vector vaccines, as The Defender previously reported, causes cells to produce the spike protein, but in a different way than the mRNA shots.

The technology uses a familiar virus — adenovirus — which is a common cause of respiratory infections. The DNA in the adenovirus is modified so that when it enters the host cell, it causes the cell’s own machinery to produce the spike protein.

The adenovirus also is modified so it cannot replicate itself, which is why it is called a replication-defective recombinant adenoviral vector vaccine.

How the study was conducted

The team of 14 researchers — led by Martina Patone, Ph.D., a data scientist and medical statistician at the University of Oxford — analyzed data for people ages 13 and older who were vaccinated against COVID-19 in England between Dec. 1, 2020, and Dec. 15, 2021.

The authors evaluated the association between vaccination and myocarditis for different ages and sex groups by tracking hospital admissions and deaths from myocarditis by age and gender and in relation to how many doses of a vaccine the person received.

In England, the three COVID-19 vaccines given to people at that time were the Pfizer, Moderna and AstraZeneca vaccines.

Roughly 20 million people got the AstraZeneca vaccine, 20 million got the Pfizer vaccine, and just over 1 million got the Moderna vaccine.

Among those admitted to the hospital for myocarditis who recently received the AstraZeneca vaccine, the researchers counted 40 deaths due to myocarditis within 1 to 28 days after a first dose and 11 deaths due to myocarditis within 1 to 28 days after a second dose.

For those who received the Pfizer vaccine, 22 individuals died of myocarditis within 1 to 28 days of receiving their first dose, 14 died of myocarditis within 1 to 28 days of receiving a second dose and 13 died of myocarditis within 1 to 28 days of receiving a third dose.

The researchers reported no cases of fatal myocarditis among those who recently received the Moderna vaccine.

However, when they used statistical methods to estimate an “incidence rate ratio” to describe how often people reported myocarditis following vaccination, they found an increased risk of developing myocarditis following all three vaccine types — especially after a second dose of the Moderna vaccine.

Following a second dose of the Moderna vaccine, they said, the increased risk ratio for developing myocarditis was 11.76 (95% CI, 7.25-19.08).

Men under age 40, as a group, showed a heightened increased risk of myocarditis following all three vaccine types.

After the first dose of the Pfizer vaccine, the increased risk ratio for men under 40 years old was 1.85 (95% CI, 1.30-2.62). It increased to 1.93 (95% CI, 1.51-2.45) after the second dose and was 1.89 (95% CI,1.34-2.67) after the third dose.

Similarly, the researchers reported a high increased risk ratio of 3.06 (95% CI, 1.33-7.03) after the first dose of the Modern vaccine for men under 40. The risk rose to 16.83 (95% CI, 9.11-31.1) after a second dose. After a third dose, the increased risk ratio was 3.57 (95% CI, 1.48-8.64).

Among men under 40 who received the AstraZeneca vaccine, the increased risk ratio for myocarditis after the first dose was 1.33 (95% CI, 1.03-1.72) and after the second dose was 1.26 (95% CI, 0.96-1.65).

The team said their findings will enable “an informed discussion of the risk of vaccine associated myocarditis.”

While this study is important because it presents the largest published series of fatal myocarditis cases and linked them to both mRNA and adenovirus COVID-19 vaccines, McCullough said another of its conclusions is “misleading.”

Researchers misleadingly claim high myocarditis risk from COVID infection

In the study, Patone’s team attempted to compare the risk of getting myocarditis due to vaccination to the risk of getting myocarditis due to a SARS infection and concluded a SARS-CoV-2 infection posed a higher risk of myocarditis compared with the risk associated with a COVID-19 vaccine.

They concluded that, in general, the “risk of hospitalization or death from myocarditis was higher after SARS-CoV-2 [COVID-19] infection than vaccination.”

McCullough said that conclusion is false. “It’s falsely worrying people that they could get myocarditis with a respiratory infection,” he said.

McCullough added:

“The Patone paper is misleading because it’s relying on ICD [International Classification of Diseases] codes of inpatients with COVID, who don’t have adjudicated myocarditis like the outpatients do.”

The ICD codes, he said, are the automated source of hospital data Patone’s team used to determine if a person had experienced myocarditis.

McCullough cited this reference in the study’s methods section:

“The primary outcome of interest was the first hospital admission caused by the myocarditis, or death recorded on the death certificate with the International Classification of Diseases, Tenth Revision code (Table S1) related to myocarditis within the study period (December 1, 2020, to December 15, 2022). We used the earliest date of hospitalization or date of death as the event date.”

The ICD codes are triggered by the measurement of cardiac troponin in the hospital, but the measurement of cardiac troponin alone may not be an indicator of actual myocarditis, according to McCullough.

“The reason the patients in the COVID group are hospitalized is due to COVID,” he said. “There’s no adjudication [proving they have an actual case of myocarditis]. There’s no indication that a cardiac MRI was done.”

McCullough continued:

“Now for the vaccine cases of myocarditis, the usual clinical practice is to have cardiac EKGs, troponins [testing], echos, cardiac MRIs — so I guarantee you that the vaccine [cases in the study] are bonafide myocarditis cases, the COVID cases are not.”

Citing a 2021 JAMA study, McCullough explained how the notion that COVID-19 infection puts people at high risk of myocarditis is not supported by research.

Since research in the early 1990s showed it was possible for coronaviruses to lead to myocarditis, researchers were understandably concerned when SARS-CoV-2 (the virus that causes COVID-19 infection) emerged in 2020 that it might cause myocarditis.

So a team of 20 researchers conducted a study in 2021 of 1,597 athletes screened for myocarditis who had a COVID-19 infection. They published their findings in JAMA, showing COVID-19 infection had a negligible association with myocarditis with less than 3% of athletes experiencing myocarditis and no reports of hospitalizations or deaths due to myocarditis.

The JAMA study authors said:

“In this cohort study of 1597 US competitive athletes with CMR screening after COVID-19 infection, 37 athletes (2.3%) were diagnosed with clinical and subclinical myocarditis.”

“So we know from large studies of the [COVID-19] respiratory infection,” McCullough said, “that the risk of myocarditis is negligible.”

In contrast, we know from the Centers for Disease Control and Prevention’s (CDC) own data that myocarditis is associated with COVID-19 vaccination, he said. “The U.S. case count that the CDC is confirming as of September 2 is 8,812 cases of myocarditis or pericarditis,” McCullough said.

He added:

“This is a massive number, and we know from papers by Tracy Hoeg, M.D., Ph.D., that the majority of these cases of myocarditis require hospitalization.”

“As a cardiologist, I would say that no case of myocarditis is mild or transient or insignificant. All of this is of extreme significance since it scars the heart. One case of vaccine-induced myocarditis is too many.”