Nausea; Diarrhea; Headache; brain fog / was just not quite right / feeling like he shouldn't be feeling like he does; Fatigue / being tired; extreme vertigo; Lightheadedness; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP).  A 76 year-old male patient received bnt162b2 (BNT162B2), administered in arm left, administration date 15Mar2021 14:00 (Lot number: EN6207) at the age of 76 years as dose 2, single for covid-19 immunisation. The patient had no relevant medical history. Concomitant medication(s) included: EXCEDRIN [ACETYLSALICYLIC ACID;CAFFEINE;PARACETAMOL] taken for headache, start date: 18Feb2021 (ongoing). Vaccination history included: Bnt162b2 (First dose; Lot Number: EN6200; Expiry date: Feb2022; left arm), administration date: 17Feb2021, when the patient was 76 years old, for Covid-19 Immunization, reaction(s): "headache", "fatigue". The following information was reported: FATIGUE (non-serious) with onset 16Mar2021, outcome "recovering", described as "Fatigue / being tired"; VERTIGO (non-serious) with onset Mar2021, outcome "unknown", described as "extreme vertigo"; NAUSEA (non-serious) with onset 17Mar2021, outcome "recovered" (Mar2021), described as "Nausea"; DIARRHOEA (non-serious) with onset 17Mar2021, outcome "not recovered", described as "Diarrhea"; HEADACHE (non-serious) with onset 17Mar2021, outcome "not recovered", described as "Headache"; FEELING ABNORMAL (non-serious) with onset 17Mar2021, outcome "recovering", described as "brain fog / was just not quite right / feeling like he shouldn't be feeling like he does"; DIZZINESS (non-serious) with onset Mar2021, outcome "unknown", described as "Lightheadedness". The events "fatigue / being tired", "extreme vertigo", "nausea", "diarrhea", "headache", "brain fog / was just not quite right / feeling like he shouldn't be feeling like he does" and "lightheadedness" were evaluated at the physician office visit. Therapeutic measures were taken as a result of headache. Additional information: Following the second dose of the Covid-19 vaccine, aside from being tired the following day, the patient did ok until about 3 days later. The patient experienced extreme vertigo, nausea, diarrhea, headache, brain fog, and was just not quite right. The patient took something every day for headaches; usually take Excedrin, once or sometimes twice daily. It was reported that the patient has seen the same physician that the reporter does. The patient experienced fatigue more seriously with the second dose of the Covid-19 vaccine beginning the second day and was still experiencing fatigue, that it was improving but still there. The patient began experiencing nausea about 2 days after receiving the second dose of the Covid-19 vaccine and that the patient was not really feeling nauseated any more. The patient experienced lightheadedness and was reported that they didn't know if this was the correct description of the patient's side effect. The patient said he just doesn't feel right and doesn't know how to describe it. In the event, just doesn't feel right, the patient was getting better, but was feeling like he shouldn't be feeling like he does. The patient was still experiencing diarrhea off and on and was still somewhat experiencing headaches.  No follow-up attempts are possible. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-2021335698 Same reporter, drug and events; different patient.