Aneurysm; bleeding on my brain; Stroke; nausea; dizziness; headache; This is a spontaneous report received from contactable reporter(s) (Other HCP). The reporter is the patient.  A 51-year-old female patient (not pregnant) received BNT162b2 (BNT162B2), on 31Aug2021 as dose 3 (booster), single (Lot number: EW0168) at the age of 51 years for covid-19 immunisation. The patient's relevant medical history included: "Known allergies: latex" (unspecified if ongoing). The patient had no covid prior vaccination. There were no concomitant medications. The patient had no other vaccine in four weeks and no other medications in two weeks. Past drug history included: Venlafaxine, reaction(s): "Known allergies: venlafaxine". Vaccination history included: BNT162b2 (Dose Number: 2, Batch/Lot No: EL3246), administration date: 15Jan2021, when the patient was 50-year-old, for Covid-19 immunization; BNT162b2 (Dose Number: 1, Batch/Lot No: Unknown. Not available/provided to reporter at the time of report completion), administration date: 24Dec2020, when the patient was 50-year-old, for Covid-19 immunization. The following information was reported: ANEURYSM (hospitalization, disability, life threatening) with onset 04Sep2021 at 09:00, outcome "recovering"; CEREBROVASCULAR ACCIDENT (hospitalization, disability, medically significant, life threatening) with onset 04Sep2021 at 09:00, outcome "recovering", described as "Stroke"; CEREBRAL HAEMORRHAGE (hospitalization, disability, medically significant, life threatening) with onset 04Sep2021 at 09:00, outcome "recovering", described as "bleeding on my brain"; DIZZINESS (hospitalization, disability, life threatening) with onset 04Sep2021 at 09:00, outcome "recovering"; HEADACHE (hospitalization, disability, life threatening) with onset 04Sep2021 at 09:00, outcome "recovering"; NAUSEA (hospitalization, disability, life threatening) with onset 04Sep2021 at 09:00, outcome "recovering". The patient was hospitalized for nausea, dizziness, headache, cerebral haemorrhage, cerebrovascular accident (hospitalization duration: 9 day(s)). The events "nausea", "dizziness", "headache", "aneurysm", "bleeding on my brain" and "stroke" required physician office visit and emergency room visit. The patient underwent the following laboratory tests and procedures: Computerised tomogram: (04Sep2021) Aneurysm had popped and caused bleeding on brain; SARS-CoV-2 test: (unspecified date) Negative. Patient had tested covid post vaccination. Therapeutic measures were taken as a result of nausea, dizziness, headache, aneurysm, cerebral haemorrhage and cerebrovascular accident which included Surgery and Medication. On 05Sep2021 (as reported) patient developed a nausea and dizziness, she went to lay down she was in bed for 24 hours, she developed a headache which caused her to go to the emergency room, They performed CT scan and she was told that an Aneurysm had popped and caused bleeding on her brain as well as caused a stroke, she was rushed into surgery to have another pending rupturing aneurysm to be coiled. All of this happened within 4 days of her covid booster.; Sender's Comments: Based on temporal association, the causal relationship between BNT162B2 and the events, nausea", "dizziness", "headache", "aneurysm", cerebral hemorrhage, cerebrovascular accident cannot be completely ruled out. 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.