Extensive antibody profiling and T-cell responses in individuals who developed postvaccine myocarditis were essentially indistinguishable from those of vaccinated control subjects, however free spike antigen was detected in the blood of adolescents and young adults who developed post-mRNA vaccine myocarditis, advancing insights into its potential underlying cause.
Circulating Spike Protein Detected in Post–COVID-19 mRNA Vaccine Myocarditis.
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.122.061025A