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A new study involving 23 million people proves a COVID-19 vaccine side effect — once labeled “misinformation” — is real.

So claimed comedian, writer and political commentator Jimmy Dore on the Monday episode of “The Jimmy Dore Show.”

Dore examined an April 21 article in the U.K.’s Express, “Vaccine Study of 23 Million Shows Risk of ‘Heart Problems’ from Moderna or Pfizer Jab.”

The article reported on an investigation published online in JAMA Cardiology on April 20: “SARS-CoV-2 Vaccination and Myocarditis in a Nordic Cohort Study of 23 Million Residents.”

The JAMA study vindicates commentators who discussed connections between heart problems and the COVID-19 vaccines months or even years ago — and who were dismissed or vilified, said Dore.

Podcaster Joe Rogan, for instance, was harshly criticized and accused of spreading “misinformation” when he first discussed the vaccine-myocarditis connection.

But according to the study, “both first and second doses of mRNA vaccines were associated with increased risk of myocarditis and pericarditis. For individuals receiving 2 doses of the same vaccine, risk of myocarditis was highest among young males (aged 16-24 years) after the second dose.”

Specifically, among young men receiving two doses of the same vaccine, between four and seven excess myocarditis and pericarditis events occurred in 28 days per 100,000 vaccinees after the second dose of the Pfizer vaccine, and between nine and 28 excess myocarditis and pericarditis events occurred per 100,000 vaccinees after the second dose of the Moderna vaccine.

The study concluded, “The risk of myocarditis in this large cohort study was highest in young men after the second SARS-CoV-2 vaccine dose” and recommended, “this risk should be balanced against the benefits of protecting against severe COVID-19 disease.”

Myocarditis is inflammation of the heart muscle that can lead to cardiac arrhythmia and death. Pericarditis is inflammation of the tissue surrounding the heart that can cause sharp chest pain and other symptoms. The Defender has featured stories of people developing myocarditis and pericarditis after COVID-19 vaccinations.

Dore pointed out that Denmark in October 2021 suspended administration of the Moderna vaccine to people younger than 18, while Sweden did the same for people under 30.

Dore also recalled the days when Kamala Harris and Joe Biden expressed hesitancy about vaccination when then-president Donald Trump endorsed it.

When people form an opinion about the vaccines based on the political climate, not on data, it shows they are either wedded to their fear or disingenuous, he said.

Watch the segment here: