recurrence of acute myocarditis; recurrence of acute myocarditis; This is a literature report.  Author describe a case of an adolescent male patient who had recurrence of acute myocarditis temporally associated with receipt of a second dose of the PfizerBioNTech mRNA COVID19 vaccine. Case Presentation: A 17-year-old male adolescent with no significant medical history came to medical attention in Jan2021 with chest pain consistent with myocarditis. Serum troponin level peaked at 506 ngmL normal < 0.04 ng/mL. Cardiac magnetic resonance imaging (cMRI) showed 2 small areas of delayed gadolinium enhancement of the left ventricular myocardium. Electrocardiogram (EKG) showed diffuse ST segment changes. Respiratory viral pathogen panel polymerase chain reaction (PCR) testing including severe acute respiratory syndrome coronavirus 2 SARSCoV2 as well as SARSCoV2 nucleocapsid IgG and IgA was negative. He received supportive care and was discharged after 6 days of hospitalization with normal cardiac testing including serum troponin, EKG and echocardiogram at 2week follow-up. On 15Apr2021 he received his first dose of the PfizerBioNTech COVID19 mRNA vaccine without any side effects noted. One day after receiving the second dose of the PfizerBioNTech COVID19 mRNA vaccine on 07May2021 he developed fever T max 101.3 degree F and body aches that responded to acetaminophen. The following day he developed sudden onset of severe burning left sided chest pain that radiated to the left shoulder and the upper left arm. He reported that the chest pain worsened with exertion and movement and was similar to that experienced during his previous episode of myocarditis. He denied any other symptoms. The patient presented to our emergency department hemodynamically stable however EKG revealed diffuse ST-segment elevations. Initial laboratory test results showed a serum troponin of 23 ng/mL , C-reactive protein of 29 mg/L normal 05 mgL and erythrocyte sedimentation rate of 5 mmh normal < 15 mmh. Respiratory pathogen panel PCR testing including SARSCoV2 was negative. SARCoV2 nucleocapsid IgG and IgA were negative and SARSCoV2 IgM antibody for the spike protein was positive consistent with recent immunization. Rheumatologic testing including antinuclear antibody test and rheumatoid factor was negative. He was admitted to the pediatric intensive care unit for telemetry and observation Initial echocardiogram revealed normal biventricular systolic and diastolic function and no evidence of regional wall motion abnormalities or an effusion. Telemetry revealed occasional isolated premature ventricular contractions. Troponin peaked at 51.37 ngmL cMRI showed low normal left ventricular ejection fraction 53% trivial pericardial effusion and subepicardial late gadolinium in the same distribution as seen in the previous episode but with interval increased enhancement. His chest pain improved with nonsteroidal anti-inflammatory drug treatment and supportive care and he was discharged after 6 days of hospitalization. At the time of discharge his troponin was 0.17 ngmL and EKG findings were normal At an outpatient cardiology visit 3 days after discharge the patients cardiac evaluation including EKG and echocardiogram was normal. Our patient had his first episode of idiopathic acute myocarditis 4 months before recurrence This recurrent episode of myocarditis may have been triggered by the vaccine administration through an autoinflammatory or autoimmune phenomenon Cardiac MRI during both illnesses demonstrated enhancement after gadolinium administration in the same distribution during both episodes. This case highlights the possibility that the COVID19 mRNA vaccine may trigger recurrent acute myocarditis in children and adolescents who have had a previous episode of acute myocarditis.  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.; Sender's Comments: Based on the information provided, the contributory role of the suspect product BNT162B2 to reported events myocarditis/disease recurrence cannot totally be excluded. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.