Acute demyelinating encephalomyelitis; Slurring his speech; Stroke; This is a spontaneous report from a contactable physician. A 35-year-old male patient received first dose bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE), intramuscular in deltoid (unknown if right or left) on 17Dec2020 at 30 ug, single for 'Preventative'. Medical history included hypertension. There were no concomitant medications.(Physician) He is calling about the Pfizer Covid 19 vaccine. States what is going on with the patient may be associated as a side effect. The patient got the vaccine two to three weeks ago, he clarifies the patient received the vaccine on 17Dec2020 and the patient ended up acutely developing (states it is a presumptive diagnosis) Acute demyelinating encephalomyelitis, states it looks like a radiologic diagnosis. The patient is an employee at hospital. When querying seriousness states it is medically significant but could be disabling but he thinks the patient will recover. Reporter seriousness for acute demyelinating encephalomyelitis: Medically significant, Hospitalization. Patient was hospitalized on Sunday and he is still admitted at this time. Dates when patient was in hospital for acute demyelinating encephalomyelitis was from 03Jan2021 to ongoing. Caller thinks the patient was flown to (Place) yesterday. The patient's mother asked the caller if the caller thought the acute demyelinating encephalomyelitis was from the vaccine and the caller responded that he did not think it was from the vaccine. He confirms the patient is still admitted in the hospital and the patient's attending neurologist is doctor. The caller heard about the patient from doctor. When querying covid vaccine dose, the caller states the standard dose is 30 mcg. This was clarified and documented as provided. The patient has not received his second dose yet. He asks if the patient should receive the second dose. He asks a general question if a pregnant patient can be given the Pfizer covid vaccine. He heard the patient had a stroke then the CFO tried to talk to him and the patient was slurring his speech. Caller spoke to the patient's mother this morning and caller told the mother that he would try to find out what is going on with the patient.  He asked that the patient get an HIV test even though he does not think the patient is at risk. Vaccination facility type was Hospital. Vaccine administered at military facility was No. None additional vaccines administered on same date of the PFIZER suspect. AE acute demyelinating encephalomyelitis require a visit to Emergency Room, not visit to physician office. Prior Vaccinations (within 4 weeks) was none. He has heard of acute demyelinating encephalomyelitis being associated with vaccines in the past and states that it is rare and usually in kids. States he saw patients that may have had acute demyelinating encephalomyelitis back in the 80s and 90s. Therapeutic measures were taken as a result of acute demyelinating encephalomyelitis (Patient will get steroids tonight pending the review of the x-ray). The outcome of the events was unknown.   Information on the lot/batch number has been requested.; Sender's Comments: The reported stroke with speech slurred, and the presumptive diagnosis of acute demyelinating encephalomyelitis (looks like a radiologic diagnosis by the reporting physician), was most likely an intercurrent disease, and unlikely causally related to the first dose bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE).  The case will be reassessed should additional information become 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.