Recurrence of myocarditis; This literature-non-study case was reported in a literature article and describes the occurrence of MYOCARDITIS (Recurrence of myocarditis) in a 27-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis.   LITERATURE REFERENCE:     The patient's past medical history included Myocarditis (First episode of myocarditis at age 20).    On an unknown date, the patient received second dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Spikevax), the patient experienced MYOCARDITIS (Recurrence of myocarditis) (seriousness criteria hospitalization and medically significant). The patient was hospitalized for 2 days due to MYOCARDITIS. At the time of the report, MYOCARDITIS (Recurrence of myocarditis) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Magnetic resonance imaging heart: Confirmed myocarditis after receiving second dose. Cardiac MRI was found to have normal biventricular size and function, but with sub epicardial delayed enhancement involving the basal inferolateral and inferior wall and distal lateral segment. Patient had no increased myocardial signal intensity on T2 imaging. On side-by-side comparison, the enhancement in the distal lateral segment was new in comparison to the cardiac MRI at the time of the first myocarditis episode.. On an unknown date, Troponin: Elevated troponin (normal value less than or equals to 0.029 ng/mL).     For mRNA-1273 (Spikevax) (Unknown), the reporter considered MYOCARDITIS (Recurrence of myocarditis) to be related.    The study was conducted on children and adults cared for at the Clinic identified through the electronic health records, who had a history of myocarditis before the COVID-19 pandemic and had subsequently received at least 2 doses of the mRNA COVID-19 vaccines.  No concomitant and treatment medications were reported.  Patient developed chest pain 2 days after receiving the mRNA -1273 vaccine.  Patient was hospitalized for 2 days and during this time he did not require any cardiac support or had any reported arrhythmias. The patient was stable at the post discharge follow-up at 6 weeks. The course was relatively benign in this patient.  Company Comment: This is a literature non-study case concerning a 27 year-old, male patient with a history of Myocarditis at the age of 20, who experienced the serious (due to medically important condition and hospitalization) expected, AESI of Myocarditis (reported as Recurrence of myocarditis), 2 days after the second dose of mRNA-1273 vaccine. He developed chest pain 2 days after receiving the mRNA-1273 vaccine. He had elevated troponin (peak 0.268 ng/mL) and on cardiac MRI recurrence of myocarditis was confirmed. It showed normal biventricular function, but with subepicardial delayed enhancement involving the basal inferolateral and inferior wall and distal lateral segment. The enhancement in the distal lateral segment was new in comparison to the cardiac MRI at the time of the first myocarditis. Patient was hospitalized for 2 days with no need for cardiac support or reported arrhythmias and was stable at outpatient follow-up at 6 weeks. Treatment was not reported. The mentioned medical history remains as a confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 29-Sep-2022: Follow up received by safety on 30-Sep-2022 has Email with FTA and contains significant information: Reporter information, literature information, medical history, lab data, and event information were updated.; Sender's Comments: Company Comment: This is a literature non-study case concerning a 27 year-old, male patient with a history of Myocarditis at the age of 20, who experienced the serious (due to medically important condition and hospitalization) expected, AESI of Myocarditis (reported as Recurrence of myocarditis), 2 days after the second dose of mRNA-1273 vaccine. He developed chest pain 2 days after receiving the mRNA-1273 vaccine. He had elevated troponin (peak 0.268 ng/mL) and on cardiac MRI recurrence of myocarditis was confirmed. It showed normal biventricular function, but with subepicardial delayed enhancement involving the basal inferolateral and inferior wall and distal lateral segment. The enhancement in the distal lateral segment was new in comparison to the cardiac MRI at the time of the first myocarditis. Patient was hospitalized for 2 days with no need for cardiac support or reported arrhythmias and was stable at outpatient follow-up at 6 weeks. Treatment was not reported. The mentioned medical history remains as a confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.