Revaccination of individuals with cardiac adverse events following COVID-19 vaccination: A Canadian Immunization Research Network study

INTRODUCTION: Myocarditis and pericarditis are well-described rare adverse events following immunization (AEFI) associated with COVID-19 mRNA vaccines. Safety data on revaccination among people with previous cardiac AEFIs are lacking. This study assessed outcomes of COVID-19 revaccination among participants assessed for cardiac AEFIs. METHODS: The Special Immunization Clinic Network database, containing data from consented participants across twelve sites, was analyzed. Cases were classified using the Brighton Collaboration Case Definitions (BCCDs) for mutually exclusive diagnoses of myocarditis, myopericarditis or pericarditis. Subjects with cardiac symptoms not meeting the BCCD and with no alternative diagnosis were categorized as chest pain/other cardiac diagnosis. Revaccination recommendations were based on physician judgment, informed by national guidelines. Participants were followed up to 42 days after revaccination to capture AEFI recurrence. RESULTS: Between January 1, 2021 and February 23, 2023, 114 participants were enrolled, including 46 with myocarditis (40.4 %), 26 (22.8 %) with myopericarditis, 11 (9.6 %) with pericarditis, and 31 (27.1 %) with chest pain/other cardiac diagnosis. Twenty-seven of 71 participants (38.0 %) who required further COVID-19 vaccine doses were recommended for revaccination. Sixteen participants were revaccinated: two with myocarditis, two with myopericarditis, two with pericarditis and 10 with chest pain/other cardiac diagnosis. Four adults had recurrent symptoms of the AEFI: 2/10 with previous chest pain/other cardiac diagnosis, one participant with previous pericarditis and multiple comorbid conditions, and one participant with previous myopericarditis who required hospitalization. CONCLUSIONS: COVID-19 mRNA revaccination may be considered for individuals with chest pain not meeting criteria for myocarditis but caution is warranted in adults with prior confirmed myopericarditis post-COVID-19 mRNA vaccination.