Scientists have found that the heart inflammation following COVID-19 vaccination was caused by a more generalized response involving immune cells and inflammation, not by antibodies created by the vaccine.
The researchers from Yale University, US, said in their study that the immune systems of these individuals got a little too revved up and over-produced cytokine and cellular responses.
In their study published in the journal Science Immunology, the researchers also ruled out some of the theorised causes of the heart inflammation and suggested potential ways to further reduce the incidence of a still rare side effect of vaccination.
When COVID-19 vaccines were first administered two years ago public health officials found an increase in cases of myocarditis, an inflammation of the heart muscle, primarily in males in their teens or early 20s who had been vaccinated with mRNA vaccines, designed to elicit immune responses specifically to the SARS-CoV-2 virus.
What was causing this reaction was, however, unclear. For this study, the Yale research team conducted a detailed analysis of immune system responses in those rare cases of myocarditis among vaccinated individuals.
Previous research had suggested that increasing the time between vaccination shots from four to eight weeks may reduce risk of developing myocarditis.
Lead researcher Carrie Lucas, associate professor of immunobiology at the university, said that, according to Centers for Disease Control and Prevention (CDC), US, findings, the risk of myocarditis is significantly greater in unvaccinated individuals who contract the COVID-19 virus than in those who receive vaccines.
She emphasised that vaccination offers the best protection from COVID-19-related disease.
The researchers hope that this new knowledge will enable further optimizing mRNA vaccines, which, in addition to offering clear health benefits during the pandemic, have a tremendous potential to save lives across numerous future applications.
