A nurse administers a Moderna Covid-19 vaccine to the resident of a housing complex in Toronto, Ontario, Canada in March 2021 ( AFP / Cole Burston)

Flawed Canadian study cited as evidence Covid-19 shots are dangerous

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Online articles and social media posts cite a Canadian study on the risk of heart inflammation following Covid-19 vaccination to claim the shots are dangerous. But the study was withdrawn at the request of its authors, who said the paper contained a "major error."

"New Study Shows 1 in 1000 Develop Heart Inflammation After Covid Vaccination; Myocarditis and Other Related Heart Conditions Have Increased Death Rate Within 5 Years," claims a September 21, 2021 article from The Gateway Pundit -- a website that has been repeatedly fact-checked by AFP.

Screenshot taken on September 30, 2021 of a Gateway Pundit article

The claim also spread on Facebook, Instagram, and in other online articles. While there is a rare risk of myocarditis/pericarditis following Covid-19 vaccination, the Canadian paper miscalculated the rate at which it occurs.

The study, titled "mRNA COVID-19 Vaccination and Development of CMR-confirmed Myopericarditis," is the latest in a series of scientific papers with poor methodology and inaccurate findings to exacerbate the crisis of online misinformation about Covid-19.

It was posted on September 16 on MedRxiv, a free platform for unpublished manuscripts. It carried a note at the top stating that the research had yet to be evaluated and "should not be used to guide clinical practice" -- something not mentioned in The Gateway Pundit's article.

Analyzing data from the Public Health Agency of Ottawa, its authors said the "incidence of myopericarditis overall was approximately 10 cases for every 10,000 inoculations" following vaccination with mRNA Covid-19 shots -- a rate far higher than had previously been reported.

But the authors withdrew the paper on September 24, explaining in a note that independent reviewers had pointed out that the paper vastly underestimated the number of Covid-19 vaccines administered during the time period of the study.

"In order to avoid misleading either colleagues or the general public and press, we the authors unanimously wish to withdraw this paper" due to a "major error pertaining to the quoted incidence data," the note says.

The Gateway Pundit's article has not been updated to reflect the withdrawal of the study.

Contacted by AFP, the University of Ottawa Heart Institute pointed to a statement on its website saying the paper cited "incorrect data vastly inflating the incidence of post-vaccine myocarditis."

"We are sorry this error led to misinformation about the incidence of post-vaccine myocarditis. Covid-19 vaccines are safe and have been proven effective against the disease. We invite anyone who has not yet received the shot to please get vaccinated," the statement added.