Circulating Spike Protein Detected in Post-COVID-19 mRNA Vaccine Myocarditis

Area of Science:

• Immunology
• Vaccinology
• Cardiology

Background:

• Myocarditis cases reported in adolescents and young adults post-mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination.
• Limited detailed immunoprofiles available for these individuals.

Purpose of the Study:

• To investigate the immunoprofiles of adolescents and young adults who developed myocarditis after SARS-CoV-2 mRNA vaccination.
• To compare immune responses between patients with post-vaccine myocarditis and healthy vaccinated controls.

Main Methods:

• Prospective blood collection from 16 hospitalized patients with post-vaccine myocarditis.
• Extensive antibody profiling, T-cell analysis, cytokine, and antigen profiling.
• Comparison with 45 healthy, age-matched vaccinated controls.

Main Results:

• Immune responses (antibody and T-cell) in myocarditis patients were similar to controls.
• Modest increase in cytokine production observed in myocarditis cases.
• Significantly elevated levels of free SARS-CoV-2 spike protein detected in patients with myocarditis, but not in controls.

Conclusions:

• mRNA vaccine-induced immune responses do not differ between individuals who develop myocarditis and those who do not.
• Presence of free spike antigen in blood may provide insight into the underlying cause of post-mRNA vaccine myocarditis.