Full blown seizure; Fatigue; Confusion; Breathing was off; breath was heavier; patient's blood pressure was very low; Real sluggish/get slow; Speech started to get slow; This is spontaneous report from a contactable consumer (patient's wife). A 58-year-old male patient received the second dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Lot Number: ER8734) via an unspecified route of administration in left arm on 04Apr2021 12:00 at age of 58-year-old at single dose for COVID-19 immunization. It also stated the patient was one of the most vulnerable against virus so he took the Covid-19 Vaccine. Medical history included ongoing cardiac failure congestive diagnosed probably 10 years ago, ongoing diabetes mellitus diagnosed probably 20 years ago, ongoing dialysis for 3.5 years. Concomitant medication included ongoing unspecified blood thinner. Caller reported that the patient didn't take any blood pressure medications and that she knew the patient took a blood thinner. Caller unable to provide further detail for the patient's medications as she doesn't have the patient's list of medications with her. The patient previously took the first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Lot number: EP7534) injected in left arm in Mar2021 at age of 58-year-old for COVID-19 immunization and experienced fatigue after the first dose of the Covid-19 vaccine. Caller reported that it was hard to determine the cause of the fatigue because the patient was on dialysis, but that the patient has been more fatigued since he received the first dose of the Covid-19 vaccine. The patient was a compromised fellow with a host of pre-existing conditions as far as heart disease, diabetes, and dialysis. Caller was calling in regard to the Pfizer Covid-19 vaccine. Caller reported that she was calling to report a bad reaction that her husband, the patient, received on Sunday, 04Apr2021, following his second dose of the Covid-19 vaccine. Approximately 3 hours after receiving the Covid-19 vaccine, the patient had a full blown seizure at 15:00 on Sunday, 04Apr2021. Caller reported that she had to call emergency responders following the patient's seizure. The patient was doing better but the experience with his seizure was quite traumatic. Caller stated that if it was going to happen, it was going to happen to us. About 3 hours after receiving his Covid-19 vaccine on 04Apr2021, the patient became real sluggish and his speech started getting slow before the seizure occurred. Caller reported that the patient made a gradual descent downwards. Caller reported that she swears the patient has not been the same as far as fatigue goes since the patient received his first dose of the Covid-19 vaccine 3 weeks prior. Caller reported that she thought the fatigue was maybe from dialysis. The patient started to get slow just before the seizure, about 2.5 hours after he received the second dose of the Covid-19 vaccine. The patient was laying down following the second dose of the Covid-19 vaccine. Caller reported that the patient's breathing was off. The patient's breath was heavier. Caller reported that after she noticed the patient's breathing was off, she asked the patient if he was ok. Caller reported that this is when she noticed that the patient's speech was really slow and that he was experiencing confusion. The patient has had no more seizure activity. The patient was still being monitored in the hospital. Caller reported that the patient didn't remember any of it. It's hard to say if the patient's sluggishness and fatigue were ongoing. Caller reported that she couldn't go see the patient while he was in the hospital but that the patient's voice sounds much stronger. For Confusion and Speech: Caller reported that the patient seems to be back/ returned to normal. Caller reported that she knew that the patient's cardiologist went to see the patient. The patient's cardiologist said that there was nothing that happened to the patient's heart, that what the patient experienced was not a heart issue, and that the event had no effect on the patient's heart. The medical staff stated that the seizure the patient experienced was related to a blood pressure drop. Caller reported that the patient's blood pressure was very low on 04Apr2021. The patient required a visit to Emergency Room for event seizure, no visit of physician office. Admitted on Sunday, 04Apr2021 for seizure, and still hospitalized. For investigations: Caller reported that the medical staff at the hospital definitely did lab work but she was not sure if any imaging was performed. Caller reported that she has no results available for tests that were performed. The outcome of events confusion and "speech started to get slow" was recovered in Apr2021, the outcome of other events was unknown.  Follow-up attempts are completed. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-2021380129 same patient, different product(dose)/event