A Study on the Clinical Course, Outcomes and Risk Factors of Myocarditis and Pericarditis After Moderna COVID-19 Vaccine

Inclusion Criteria: * For the Elasomeran-Moderna vaccination targeting SARS-CoV-2-exposed case-cohort study, a cohort will be defined including participants of all ages with (1) at least one dose of Moderna vaccination targeting SARS-CoV-2 administered during the study period, (2) at least one year of enrolment in the applicable database prior to the index vaccine dose to allow for ascertainment of baseline covariables and potential risk factors, and (3) no myocarditis or pericarditis events within 6 months prior to Moderna vaccination targeting SARS-CoV-2 receipt. Myocarditis and pericarditis cases are defined when adjudication criteria similar to Centers for Disease Control and Prevention (CDC) case definition for probable or definite myocarditis or pericarditis is fulfilled. * For the cohort study, participants will be included if they: (1) meet the adjudication criteria similar to the CDC case definition for probable or definite myocarditis or pericarditis, (2) have at least one year of enrolment in the applicable database prior to the index myocarditis or pericarditis event to allow for ascertainment of baseline covariates and potential risk factors, and (3) have not received a COVID-19 vaccine other than Moderna vaccination targeting SARS-CoV-2 within 30 days prior to the index myocarditis or pericarditis event. Exclusion Criteria: * Participants who have evidence of myocarditis or pericarditis in structured data (for example: ICD-10 codes) where review of clinical data is incompatible with adjudication criteria similar to CDC case definition for myocarditis or pericarditis will be described but will not be included as cases in primary analyses. * In the Moderna vaccination targeting SARS-CoV-2-exposed case-cohort design, these non-confirmed myocarditis/pericarditis cases will be censored at the onset of the false positive myocarditis/ pericarditis diagnosis.