could not get her head around what day it was/ her brain was not working right; disoriented/disorientation; body not responding/she couldn't function; This is a spontaneous report from a contactable Other Health Professional (patient). An 84-year-old female patient received first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE) on 28Dec2020 by injection once to right deltoid (Batch/lot number: EL0142), second dose of BNT162B2 via an unspecified route of administration on 18Jan2021, both at single dose for COVID-19 immunization. There were no medical history and concomitant medications. Investigation Assessment: No. The patient had second her COVID shot, the vaccine, on 18Jan2021, and she is a very healthy 84 years old with no health problems, and she woke up on 19Jan2021, and was disoriented, she could not get her head around what day it was, this was so rare, she normally goes to the fitness center and excursuses, but her body was not responding, her brain was not working right, it was a strange ordeal, so she got in the shower, to get her circulation going, and she couldn't shower, she got all wet, and had to get out and lay on a towel, she couldn't function, it was very scary, and very atypical. Her disorientation went away by 10AM on 19Jan2021- she did not see anyone or go to a provider. Her body started not responding around 7:30 when she got up, and by 9 or 10AM, she was functioning again. The patient didn't think this was from vaccine, she had seen enough vaccine reactions to various vaccines, and this was not a vaccine reaction, she thought what is happening? Is this a stroke, or a vascular event, she has since recovered but was still very shook, anxious about what it was, what happened until an hour or so after, it was still under her. Causality: Unknown, she didn't think of the connection until someone else did, she was describing it and the other person said it was because of the vaccine, as this person was a skeptic and doesn't want the vaccine herself, and this was not a typical response, but then she got to thinking. The outcome of disoriented/disorientation and body not responding/she couldn't function was recovered on 19Jan2021, the other event was unknown. Seriousness: it was disabling at the time, she was concerned she had a stroke, she was checking her grasps and her face and legs, she was obsessing. Seriousness for disoriented/disorientation and body not responding/she couldn't function was disability.  Information about lot/batch number has been requested.; Sender's Comments: A possible causal association between administration of BNT162B2 and the onset of serious events cannot be excluded, considering the plausible temporal relationship.  The underlying medical conditions in the advanced old patient considered confounders. 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