The overall risk of heart inflammation (myopericarditis) following Covid-19 vaccination is very low, affecting 18 people per million vaccine doses, a study in The Lancet Respiratory Medicine has found. The researchers found no statistically significant difference between the incidence of myopericarditis following the Covid-19 vaccination and other vaccinations (56 per million).
The condition: Myopericarditis is a condition that causes inflammation of the heart muscle and, in some cases, severe permanent heart damage. It is most often caused by viruses, but in rare instances can also occur after vaccination.
DATABASE: The researchers looked at more than 400 million doses from global databases, and analyzed more than 20 studies with reported incidences of myopericarditis following any type of vaccination between January 1947 and December 2021.
Of these, 11 studies looked specifically at Covid-19 vaccinations, covering over 395 million doses – nearly 300 million of which were mRNA vaccines. The rest of the studies covered other vaccinations such as smallpox (2.9 million doses), influenza (1.5 million doses), and others (5.5 million doses).
“The occurrence of myopericarditis following non-Covid-19 vaccination could suggest that myopericarditis is a side effect of the inflammatory processes induced by any vaccination and is not unique to the SARS-CoV-2 spike proteins in Covid-19 vaccines or infection,” said co-author Dr. Jyoti Somani, an infectious diseases specialist at National University Hospital, Singapore.