Pediatria pre prax 1/2023

Myocarditis after COVID-19 infection and after COVID-19 mRNA vaccination

Documented pediatric cases of COVID-19 infection represent 1–5 % of confirmed infections, while the risk of a severe course is present especially in high-risk groups of children. The SARS-CoV-2 coronavirus, unlike other coronaviruses, is significantly cardiotropic, as evidenced by the described cases of myocardial damage during the pandemic. In children, it is often a subclinical course, which is why the return to high physical activity should be gradual after overcoming the infection. A new diagnostic entity that appeared during the pandemic is the multisystem inflammatory syndrome associated with COVID-19 infection (MIS-C), often accompanied by hemodynamic instability and depressed ventricular function. The prognosis of the disease is excellent with early intensive treatment, without chronic residual involvement of the myocardium. Immunization of children with mRNA vaccines is associated with a lower need for hospitalization and a lower incidence of MIS-C. Potential benefits are also the prevention of the so-called long covid/post-covid syndrome, reduction of the spread of infection in the population with a reduction of the risk of emergence of new resistant variants and safe school attendance. Vaccine-associated myocarditis has become the most feared but very rare side effect of vaccination. These cases were mostly observed in adolescent boys after the second dose of COVID-19 mRNA vaccines. Almost exclusively, the disease course was mild with rapid clinical improvement. However, cardiological follow-up of these patients is essential, because persistent myocardial changes on magnetic resonance imaging have been described in a small proportion of them. In summary, two years of the pandemic have shown that COVID-19 itself is associated with a substantially higher risk of myocarditis and other cardiac complications compared to vaccination.

Keywords: COVID-19 infection, myocarditis, MIS-C, vaccination