Recent peer-reviewed studies and systematic reviews have raised concerns about adverse effects linked to COVID-19 mRNA vaccines, particularly myocarditis and other cardiac complications. Research published in journals such as ESC Heart Failure and BMJ Open highlights instances of myocarditis leading to severe outcomes including cardiac arrest and sudden death. A Korean nationwide study, autopsy reports, and meta-analyses have documented increased risks of myocarditis and pericarditis in populations receiving mRNA COVID-19 vaccines compared to unvaccinated groups. Additionally, investigations into the intracellular aggregation of spike protein monomers encoded by these vaccines suggest potential mechanisms for cardiac side effects. Several multi-author papers, including one with 11 authors and over 150 references, have examined the broader spectrum of harms associated with COVID-19 injections. Some experts and studies argue that the risks of mRNA vaccines may outweigh theoretical benefits, noting the absence of prospective, double-blind, randomized, placebo-controlled trials. Recent calls from researchers urge immediate market withdrawal of COVID-19 mRNA vaccines based on accumulating evidence of adverse cardiac events and other serious harms.