A Canadian COVID-19 study that turned out to be wrong has spread like wildfire among anti-vaxxers

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An inaccurate Canadian study suggesting an extremely high rate of heart inflammation after COVID-19 vaccines has been retracted due to a major mathematical error — but not before it spread like wildfire on anti-vaccination websites and social media.

The preprint study, which was released by researchers at the Ottawa Heart Institute last week but has not been peer-reviewed, looked at the rate of myocarditis and pericarditis cases after Moderna and Pfizer-BioNTech vaccinations in Ottawa from June 1 to July 31.

The study identified 32 patients with the rare side effects out of a total of 32,379 doses of mRNA vaccines given in Ottawa in the two-month period, finding an inordinately high rate of close to 1 in 1,000 — significantly higher than other international data has shown.

But the researchers made a critical error that experts say caused the study to be "weaponized" by the anti-vaccination movement at a time when concern over COVID-19 vaccine side effects are top of mind for parents whose kids may soon get the shot.

The researchers mistakenly failed to record the accurate number of vaccinations given out during that two-month period, despite the data on total doses being publicly available, and the figure turned out to be astronomically higher than what was presented in the study. 

Instead of 32,379 mRNA vaccine doses administered in June and July, as the study suggests, there were actually more than 800,000 shots given out at that time, according to Ottawa Public Health.