See earlier blog, “Covid-19 Myocarditis” is Not an Actual Syndrome: The Only Controlled Epidemiologic Data, & a Review of Autopsy/ Biopsy Data Support That Conclusion”
Study Methods Overview
“This is a retrospective cohort study examining the incidence and prevalence of acute inflammatory heart diseases (myocarditis, pericarditis, myopericarditis, and perimyocarditis) in the Tuscany area including the provinces of Pisa, Lucca, and Livorno (total population of 1 141 285 inhabitants) by comparison of two time intervals of 1 year each: prior to the COVID-19 (PRECOVID, from 1 June 2018 to 31 May 2019) and during the pandemic period (COVID, from 1 June 2020 to 31 May 2021). We excluded the time between June and December 2019 as we could not rule out the presence of SARS-COV2 in Italy during this period. Yet, we excluded the time between January and May 2020 because of the strict lockdown in Italy. Clinically suspected myocarditis occurring within 10 days from a SARSCOV2 dose of vaccination were excluded because it was iatrogenic myocarditis…We decided to consider as the ‘COVID period’ the time between 1 June 2020 and 31 May 2021 based on several reasons: to avoid the effect of the ‘strict’ lockdown of the first months of 2020; stopping the evaluation on 31 May 2021 was also useful to exclude patients with myocarditis following anti-COVID vaccination that could have been a confounding factor, altering the incidence and prevalence of myocarditis; in the last months of 2021 a great percentage of the Italian population was vaccinated for COVID-19 and the vaccination could have mitigated the risk of myocarditis caused by COVID-19.”
“A diagnostic algorithm adapted from the European Society of Cardiology guidelines was used to diagnose acute myocarditis.”
“Comparison of rates tests and the measurement of the incidence rate ratio (IRT) was performed to compare the annual incidence of myocarditis and pericarditis during the PRECOVID and COVID time periods. Statistical significance was defined as a P-value less than 0.05. Statistical analysis was performed using MedCalc software (version 20.0.14, MedCalc Software Ltd, Ostend, Belgium).”
(See Figure and Table, below, followed by study abstract, and link to full, downloadable pdf of study)
—The annual incidence of myocarditis was significantly higher in the PRECOVID than in the COVID period, 8.1/100 000/year vs. 5.9/100 000 year, respectively, a net reduction during COVID of 27% (p=0.047).
—Driving the overall differences in the incidence of myocarditis was a significant decrease in cases of myocarditis among those aged 17 and 34 years. In particular, the incidence of myocarditis was significantly lower during COVID, compared to the PRECOVID period for those aged 18–24 years old (p=0.048).
Download full pdf of study, here: Italian Data on myopericarditis pre and post C19 pandemic