This article was originally published in German on Coliquio.
Researchers have raised concerns about a potentially increased risk of myopericarditis in connection with COVID-19 vaccination, but new data provide an all-clear signal. A meta-analysis of 22 studies has revealed that the rate of myopericarditis is no higher after COVID-19 vaccination as after other common vaccinations and that it may be lower in some cases.
For their analysis, Ryan Ruiyang Ling, MBBS, a student at the Yong Loo Lin School of Medicine at the National University of Singapore, and his team evaluated data from four international databases. In addition to COVID-19 vaccinations (n = 395 million, 300 million of which are mRNA vaccines), they examined data for vaccinations against smallpox (n = 2.9 million), influenza (n = 1.5 million), and other infectious diseases (n = 5.5 million) that were administered between January 1947 and December 2021.
The total incidence of myopericarditis per million COVID-19 vaccinations was 18 cases. This was significantly lower than for the other vaccines, for which there was an average of 56 cases/million vaccine doses. At 132 cases/million vaccine doses, smallpox vaccination was determined to have the highest risk.
For people younger than 30 years (40.9 cases/million vaccine doses) and for men (23 cases/million), the risk of myopericarditis after COVID-19 vaccination was somewhat higher. Also, a somewhat higher risk was noticed in association with mRNA vaccines (22.6 cases/million) and with second vaccinations (31.1 cases/million) in comparison with all COVID-19 vaccinations in the general population. More than 90% of those who developed myocarditis after vaccination with an mRNA vaccine were men whose average age was 25 years.
One limitation of the study was that the analysis included a low proportion of persons younger than 12 years, which calls the transferability of the results for this age group into question. The risk does not seem to be higher for vaccinated people older than 12 years than with other vaccinations, and the benefits of the vaccination far outweigh the risk, the authors say. An explanation for the myocarditis cases, even with other vaccinations, could be a general post-vaccination inflammatory reaction, which in rare cases can affect the heart.