Myocardial and Vascular Involvement in COVID-19 and Post-Vaccination States: Understanding Injury Pathways and Clinical Implications

Myocardial and vascular injury secondary to SARS-CoV-2 infection and vaccination has emerged as a clinically relevant phenomenon, with distinct but overlapping mechanisms. Myocardial injury in COVID-19 results from a complex interplay between direct viral effects and immune-mediated inflammation, supported by histopathological studies revealing macrophage-rich infiltrates, microthrombosis, and supporting fibrosis in isolated areas. In contrast, vaccine-associated myocarditis—reported predominantly following mRNA vaccines—has a self-limiting clinical course, with mechanisms likely involving molecular mimicry, aberrant immune activation, or hypersensitivity reactions, although these pathways require further validation. Although mRNA vaccines have been associated with a small increase in myocarditis, particularly in young men, the risk is significantly lower than that associated with COVID-19 infection, and the cardiovascular benefits of vaccination far outweigh these rare adverse events in most populations. After the end of the pandemic, the number of patients with severe forms of COVID-19 has decreased significantly, but we consider that cardiac involvement remains an important issue for the acute and long-term prognosis of patients with SARS-CoV-2 infection. Our paper synthesizes the latest epidemiological and mechanistic evidence on the link between COVID-19, vaccination, and myocardial and/or vascular injuries, highlighting the clinical implications and providing practical recommendations for management, as well as future perspectives on risk assessment, targeted immunotherapy, advanced diagnostic tools, and long-term monitoring.