Pericarditis; ASSESSMENT OF RISK FACTORS FOR MYOCARDITIS USING ELECTRONIC HEALTH RECORDS AND CLAIMS DATA  This is a non-interventional study report received from a contactable reporter(s) (Other HCP) for protocol C4591055.  A female patient received BNT162b2 (BNT162B2), on 27Aug2021 as dose 1, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "Chronic Chest Pain", start date: Jun2020 (ongoing), notes: Pertinent Details: Patient reported discomfort on her sides and under breast for several months. The patient's concomitant medications were not reported. The following information was reported: PERICARDITIS (hospitalization) with onset 29Aug2021, outcome "recovering". The patient was hospitalized for pericarditis (start date: 06Sep2021, discharge date: 08Sep2021, hospitalization duration: 3 day(s)). The patient underwent the following laboratory tests and procedures: C-reactive protein: normal; Echocardiogram: normal; Electrocardiogram: improved, notes: Repeat EKG improved from previous EKG and the ST depressions resolved; Fibrin D dimer: normal; Magnetic resonance imaging: no results available at this time; Red blood cell sedimentation rate: normal; Troponin: normal. Therapeutic measures were taken as a result of pericarditis.Clinical course: Patient is a healthy female who recently had a COVID-19 Pfizer injection on 27Aug2021, 2 days later she experienced pleuritic chest pain. She was evaluated at an urgent care facility and was prescribed metolazone on 29Aug2021 symptoms did not improve therefore she was admitted to hospital on 06Sep2021. Her symptoms improved with the addition of colchicine. There was no ability to perform an MRI prior to discharge to evaluate the heart for myocarditis. An echocardiogram was performed and documented as "normal". Patient also had normal cardiac enzymes (Troponin), CRP, ESR, d-dimer. Chest pain was reproducible with certain movements and deep breathing leading to a question whether it was musculoskeletal or related to pericarditis. Repeat EKG improved from previous EKG and the ST depressions resolved. Her chest discomfort was worse when she laid flat or moved to one side. Chest pain - Pleuritic Symptoms documented by the healthcare provider "seemed consistent with pericarditis vs myocarditis, possibly related toto the COVID-19 vaccine" Date of Discharge 08Sep2021. Discharge Diagnoses Pericarditis. Patient was to have a MRI as outpatient - no results available at this time. Study Drug (Trade and Generic), Formulation, Route, Indication: Pfizer Covid-19 Vaccine/ First injection; Check box if Pfizer Drug: Checked; Dose: unk; Units: unk; Frequency: 1. Adverse Event Term: Pericarditis; Is the event serious? Yes. Did an SAE/AE recur with re-administration of drug? Not Applicable. The investigator considered there was a reasonable possibility that the event was related to study drug (Covid-19 mRNA Vaccine), there was not a reasonable possibility that the event was related to concomitant drug.  The reporter considered "pericarditis" related to BNT162b2.  Follow-up attempts are completed. No further information is expected.; Sender's Comments: Based on temporal association and currently known product profile, the event pericarditis is considered related to BNT162b2. 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.