According to findings published in The Lancet Respiratory Medicine, the risk of COVID-19 vaccine leading to myopericarditis is low.
Prior to the pandemic, myopericarditis, an uncommon complication of vaccination, was only related to smallpox vaccination. However, as of March 2022, with more than 10 billion doses of COVID-19 vaccines dispensed, reports of myopericarditis have increased significantly and studies have suggested a link to the COVID-19 vaccination, especially in men aged younger than 30 years.
Researchers sought to compare the incidence of myopericarditis following COVID-19 and non-COVID-19 vaccination to determine the risk for myopericarditis in subpopulations receiving COVID-19 vaccinations. They also sought to quantify the incidence of myocarditis, pericarditis, and mortality after receiving a vaccine. The primary outcome was myopericarditis following vaccination.
To accomplish this, they conducted a systematic review and meta-analysis of 22 studies from MEDLINE, Embase, Cochrane, and Scopus databases. The review and analysis was done on 405,272,721 vaccine doses from January 1947 through December 2021. This included 11 studies reporting on 395,361,933 COVID-19 vaccine doses. The balance reported on smallpox, influenza, and an assortment of non-COVID-19 vaccines.
The difference in incidence of myopericarditis among subpopulations was analyzed, stratifying for vaccine (COVID-19 vs non-COVID-19), age (adult vs pre-adult), sex, and sub-stratifying for mRNA vs non-mRNA in COVID-19 vaccines. The researchers also used the Grading of Recommendations, Assessment, Development and Evaluations approach to assess the certainty of their evidence (low-high).