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The small preprint study by the University of Ottawa Heart Institute, Canada’s “largest and foremost” heart centre, was alarming, suggesting that, based on a sample size of just 32 people, Pfizer and Moderna COVID-19 vaccinations carry an estimated one in 1,000 risk of heart inflammation.The scientists initially estimated the prevalence of myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the outer lining of the heart) based on 32 consecutive people admitted to the Heart Institute from June 1 through to the end of July 2021 with a suspected diagnosis of post-vaccination heart inflammation.The authors calculated that, during the same study period, a total of 32,379 doses of Pfizer and Moderna vaccines were administered in the Ottawa area. “Therefore, if our cohort captured all cases in the Ottawa area, then the incidence of myocarditis would be 0.1 per cent of all vaccine doses,” or 10 cases of myocarditis for every 10,000 doses of vaccine, they wrote.The researchers said the data collected on vaccine doses came from an Ottawa Public Health open database.Except their denominator was wrong.Ottawa Public Health confirmed to the National Post that, during the study period, more than 833,000 mRNA (Pfizer of Moderna) COVID-19 vaccinations were administered in Ottawa.The adjusted incidence is about four per 100,000 doses, which is within the range of recent studies, and vastly lower than the initial estimate.