Myocarditis; This is a solicited report received from non-contactable reporter(s) (Consumer or other non HCP). The reporter is the parent. Other Case identifier(s): US-UGNX-22-00704.  A 17-year-old male patient received BNT162b2 (BNT162B2), as dose number unknown (booster), single (Batch/Lot number: unknown) for covid-19 immunisation; triheptanoin (DOJOLVI), since Mar2017 (ongoing) (Batch/Lot number: unknown), oral for carnitine palmitoyltransferase deficiency. The patient's relevant medical history included: "Carnitine palmitoyltransferase deficiency" (ongoing); "long-chain fatty acid oxidation disorder" (ongoing). The patient's concomitant medications were not reported. Vaccination history included: Covid-19 vaccine (Primary Immunization series completed;  unknown manufacturer), for Covid-19 immunization. The following information was reported: MYOCARDITIS (medically significant) with onset 28Sep2022, outcome "unknown". The patient underwent the following laboratory tests and procedures: Heart rate: 125, notes: heart rate was 125 all day. The action taken for triheptanoin was dosage not changed.  The reporter's assessment of the causal relationship of "myocarditis" with the suspect product(s) BNT162b2 was not provided at the time of this report. Since no determination has been received, the case is managed based on the company causality assessment.  Clinical Course: The patient got Myocarditis from his booster which is rare (Myocarditis). A solicited (medically confirmed) case from country, initially received from the patient's mother via Market research on 28Sep2022 with additional information received on 30Sep2022 and 04Oct2022. This case refers to a 17-year-old male patient who got myocarditis from his booster which was rare while receiving Dojolvi (triheptanoin) for the treatment of long-chain fatty acid oxidation disorder (LC-FAOD): carnitine palmytoiltransferase II (CPT II) deficiency. On an unspecified date in Mar2017, the patient started on the Dojolvi compassionate youth trial and continued on Dojolvi (triheptanoin) commercially (lot number, dose and frequency were not provided. On 28Sep2022, the patient's mother reported that the patient woke up 'really lethargic and couldn't eat and his heart rate had been 125 all day. The patient's mother thought the patient needed to be seen and stated that the patient got 'myocarditis from his booster which is rare'. The patient's mother did not specify to which medication 'booster' refers to. Confirmation is pending with reporter/HCP if this refers to COVID-19 booster. Treatment with Dojolvi was reported as 'ongoing'.  Company Remarks (Sender's comments): Company comment: Myocarditis is an unexpected adverse event for Dojolvi. The company assessed the event of serious (medically important events). Considering the missing information regarding the patient's medical history, etiology of the event as well as the medication 'booster' that the patient received the Company considers causality for the event of myocarditis not assessable.  The information on the batch/lot number for BNT162b2 has been requested and will be submitted if and when received.; Sender's Comments: As there is limited information in the case provided, the causal association between the reported events with the suspect drug BNT162B2 cannot be excluded. The case will be reassessed once new information is available. 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.