Some kind transient blood clot or ischemic accident of some sort; Some kind transient blood clot or ischemic accident of some sort; I had a bad headache and I was really tired; I had a bad headache and I was really tired; Something did interfered in the blood flow; My body went limp like a noodle; I could not walk actually, my whole body lost function for short period of time; My body went limp like a noodle; I could not walk actually, my whole body lost function for short period of time; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 68-year-old female patient received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), on 28Sep2022 as dose number unknown (booster), single (Lot number: GH9703) at the age of 68 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "Prediabetes" (unspecified if ongoing), notes: Prediabetes; "Cancer" (ongoing), notes: Cancer, I am on chemotherapy with cancer and I take 5FU that is my chemotherapy drug every two weeks. Concomitant medication(s) included: METFORMIN; LANTUS; ACYCLOVIR [ACICLOVIR]; PROGESTERONE; LATANOPROST taken for eye disorder; FLUOROURACIL 5 FU taken for chemotherapy, neoplasm malignant. Vaccination history included: Covid-19 vaccine (Primary Immunization series complete but unknown manufacturer), for COVID-19 immunization. The following information was reported: SENSORY DISTURBANCE (non-serious), GAIT DISTURBANCE (non-serious) all with onset 2022, outcome "unknown" and all described as "My body went limp like a noodle; I could not walk actually, my whole body lost function for short period of time"; CARDIOVASCULAR DISORDER (non-serious) with onset 2022, outcome "unknown", described as "Something did interfered in the blood flow"; HEADACHE (non-serious) with onset 28Sep2022, outcome "recovered" (29Sep2022), FATIGUE (non-serious) with onset 28Sep2022, outcome "unknown" and all described as "I had a bad headache and I was really tired"; THROMBOSIS (medically significant), ISCHAEMIC SKIN ULCER (non-serious) all with onset 30Sep2022, outcome "unknown" and all described as "Some kind transient blood clot or ischemic accident of some sort". The patient underwent the following laboratory tests and procedures: Computerised tomogram: all my vessels were clear, notes: They did CT scan, they did MRI, all my vessels were clear; Echocardiogram: Not Provided; Magnetic resonance imaging: all my vessels were clear, notes: They did CT scan, they did MRI, all my vessels were clear. They did MRI scan for both my brain and neck; Magnetic resonance imaging head: My brain scan and everything was clear, notes: They did MRI scan for both my brain and neck. My brain scan and everything was clear but something did happen where something interfered in the blood flow. Therapeutic measures were taken as a result of thrombosis, ischaemic skin ulcer, headache, fatigue, cardiovascular disorder, sensory disturbance, gait disturbance.  Additional information: Consumer stated, I had a very strange incident happened on Friday last week. It appears there is some kind transient blood clot or ischemic accident of some sort and I am calling because I have no conditions in my vessel, they did my CT in the emergency room because I could not walk actually, my whole body lost function for short period of time. They did CT scan, they did MRI, all my vessels were clear. I do not have any history of anything like this. So, the reason it cleared up shortly after 90 min after it happened and when back tracked on the Wednesday in the afternoon, I had my Pfizer Bivalent booster and by evening I had a bad headache and I was really tired but I figured it was just a side effect. The next day I felt okay headache was gone but I was still little tired but I worked. And it was the next morning so less than probably about 30 to 36 hours later I had this incident happened. I now talked to number of different doctors because aside from having no other reason for having this event happened physiologically. I am on chemotherapy with cancer and I take 5FU that is my chemotherapy drug every two weeks (Further the name of medication was not clarified). So, on talking with my oncologist yesterday she says, I do not think it is TIA because nothing detected in my vessels or no plaque build up even though I am older. My brain scan and everything was clear but something did happen where something interfered in the blood flow. So, basically my body went limp like a noodle and then after about an hour it started, it ended. So, here I really had a question whether or not I was having a reaction and small blood clot that dissolve quickly from the injection that I had 30 hours earlier. When paraphrased the concern: Consumer stated I am wanting to share with you all that experience in case this is something if other people is also experiencing as an after market effect and if you all do know if this is been happening to other people so I would like to know that. I want to know if it has happened to others can I expect to happen again I certainly would like to know if this is something I would expect to happen again and if it was just possibly an immediate effect. Consumer was informed about the role of Pfizer Drug Safety Department and about Pfizer Medical Information Department for the questions. Other medication: Consumer stated, I take T3, T4. I take compound of 'YSGATA and Testosterone'. Lab test: Consumer stated While I was in the hospital they did multiple blood draws. They did CT scan with and without contrast. They did MRI scan for both my brain and neck. They did an echocardiogram with a bubble test I suppose and I am scheduled for an ultrasound for my Carotid artery next week and I am going to see a neurologist but I do not have the appointment. Prior vaccination (within 4 weeks): Consumer stated, no, just this vaccine.