This is a low-interventional cohort study to determine cardiac and non-cardiac long-term outcomes of persons <21 years of age with myocarditis/pericarditis after the administration of COMIRNATY, compared with similarly aged persons with myocarditis/pericarditis associated with COVID-19, including MIS-C.~To be classified as having COMIRNATY-associated myocarditis/pericarditis, a person must 1) meet the CDC case definition for probable or confirmed myocarditis/pericarditis,15 2) have received any dose of COMIRNATY ≤ 7 days of symptom onset, and 3) have no other plausible alternative etiology at the time of enrollment. Inclusion criteria for participants are:~Age <21 years~Presentation to a participating medical center with evaluation in Emergency Room and/or hospitalization~Received either the 1st, 2nd, 3rd or booster dose(s) of COMIRNATY ≤7 days of symptom onset, even if a different brand of COVID-19 vaccine had been administered in earlier vaccinations Retrospectively ascertained participants must be enrolled within 2 years of diagnosis~COVID-19 related disease~Probable or confirmed myocarditis/pericarditis as per the contemporaneous CDC case definition at the time of diagnosis~Capable of giving signed informed consent/assent (by parents/legal guardians of minors and/or patients), which includes compliance with the requirements and restrictions listed in the Informed Consent/Assent Document and in this protocol OR meets criteria for waiver of consent.~To be classified as having myocarditis/pericarditis associated with COVID-19, a person must have 1) either acute severe COVID-19 infection or MIS-C, as defined by the CDC, 2) findings of probable or confirmed myocarditis in the CDC definition, 3) no other plausible alternative etiology.~Participants in all cohorts will be those who present to participating medical centers for care. This study is a collaboration between the National Heart, Lung, and Blood Institute (NHLBI)'s Pediatric Heart Network (PHN) and Pfizer.~Approximately 300 prospectively ascertained cases of children, adolescents, and young adults <21 years of age who receive care at participating medical centers for myocarditis/pericarditis associated with COMIRNATY, up to 200 retrospectively ascertained cases of persons <21 years of age who receive care for myocarditis/pericarditis associated with COMIRNATY, and approximately 100 persons <21 years of age with COVID-associated myocarditis/pericarditis, including MIS-C will be enrolled.
The purpose of this clinical trial is to learn about the safety and effects of the study vaccine (called COMIRNATY) for the potential prevention of COVID-19. This study is seeking participants who:~Are age <21 years.~Have presentation to participating medical center with evaluation in Emergency Room and/or hospitalization.~Received either the 1st, 2nd, 3rd or booster dose(s) of COMIRNATY within 7 days of symptom onset.~Meet criteria of Centers for Disease Control and Prevention case definition of probable or confirmed myocarditis/pericarditis~Are capable of giving signed informed consent/assent (by parents/legal guardians of minors and/or patients), which includes compliance with the requirements and restrictions listed in the Informed Consent/Assent Document and in this protocol OR meets criteria for waiver of consent.~This study will examine the potential long-term effects associated with myocarditis/pericarditis following vaccination with COMIRNATY. The association of myocarditis/pericarditis in participants who received the study vaccine (COMIRNATY) compared with those associated with COVID-19 will also be examined. This will help us determine if COMIRNATY is safe and effective, and if there is a myocarditis/pericarditis association that should be noted. Participants will take part in this study for up to 5 years. During this time, they will receive complete cardiac imaging tests, and have follow up visits per guidance stated in the study protocol.