leukopenia; neutropenia; worsening leukopenia and neutropenia; new blast cells; injury; leukemia; This is a spontaneous report received from a non-contactable reporter(s) (Physician).  An 80-year-old male patient received BNT162b2 (BNT162B2), on 02May2022 as dose 4 (booster), single (Lot number: FM7553) at the age of 80 years intramuscular, in left arm for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Patient was not diagnosed with COVID prior to vaccination and was tested for COVID since vaccination. Vaccination history included: BNT162b2 (Dose 1, Lot number: EN6198, dose administrator route: Intramuscular, dose vaccine location: Left arm), administration date: 26Feb2021, when the patient was 79-year-old, for COVID-19 immunization; BNT162b2 (Dose 2, Lot number: EP6955, dose administrator route: Intramuscular, dose vaccine location: Left arm), administration date: 19Mar2021, when the patient was 79-year-old, for COVID-19 immunization, reaction(s): "Leukopenia", "neutropenia"; BNT162b2 (Dose 3, Lot number: FE3590, dose administrator route: Intramuscular, dose vaccine location: Left arm), administration date: 18Oct2021, when the patient was 79-year-old, for COVID-19 immunization, reaction(s): "Leukopenia", "neutropenia", "splenomegaly". The following information was reported: INJURY (hospitalization, life threatening) with onset 08Sep2022, outcome "not recovered"; LEUKAEMIA (hospitalization, life threatening) with onset 08Sep2022, outcome "not recovered", described as "leukemia"; LEUKOPENIA (hospitalization, life threatening) with onset 08Sep2022, outcome "not recovered"; NEUTROPENIA (hospitalization, life threatening) with onset 08Sep2022, outcome "not recovered"; BLAST CELLS PRESENT (hospitalization, life threatening) with onset 08Sep2022, outcome "not recovered", described as "new blast cells"; CONDITION AGGRAVATED (hospitalization, life threatening) with onset 08Sep2022, outcome "not recovered", described as "worsening leukopenia and neutropenia". The patient was hospitalized for leukopenia, neutropenia, condition aggravated, blast cells present, injury, leukaemia (start date: Sep2022). The events "leukopenia", "neutropenia", "worsening leukopenia and neutropenia", "new blast cells", "injury" and "leukemia" required physician office visit and emergency room visit. The patient underwent the following laboratory tests and procedures: Biopsy bone marrow: (Sep2022) Unknown results; Blast cells: (08Sep2022) New blast cells; SARS-CoV-2 test: (08Sep2022) Negative; Ultrasound scan: (Sep2022) Unknown results, notes: diagnosis being confirmed and then treatment will be discussed. Therapeutic measures were taken as a result of leukopenia, neutropenia, condition aggravated, blast cells present, injury, leukaemia. Bone marrow biopsy, ultrasound-diagnosis being confirmed and then treatment will be discussed.  Clinical course: Patient had his 4th dose of COVID vaccine 02May2022. On 08Sep2022 he presented to the ED for an unrelated injury and was found to have worsening leukopenia and neutropenia and new blast cells. This patient is scheduled for bone marrow biopsy to confirm leukemia diagnosis. This patient was scheduled for bone marrow biopsy to confirm leukemia diagnosis. It was reported that the events resulted in doctor or other healthcare professional office/clinic visit, emergency room/department or urgent care, hospitalization (Sep2022), and life-threatening illness (immediate risk of death from the event).  The reporter considered "injury" not related to BNT162b2.  No follow-up attempts are possible. No further information is expected.; Sender's Comments: Based on the available information in the case, the causal association between the events leukopenia, neutropenia, condition aggravated, blast cells present, leukemia and the suspect drug BNT162B2 cannot be excluded and event injury unrelated to the suspect drug 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.,Linked Report(s) : US-PFIZER INC-202201150632 Same patient, same drug, different dose;US-PFIZER INC-202201156107 Same patient, same drug, different dose;