Having problems thinking straight; Sometimes asked questions and doesn't know what to answer; Devastating fatigue; When speaking, in the middle of a sentence I can't remember the words I want to say /Keeps forgetting things; This is a spontaneous report received from contactable reporter(s) (Other HCP) from medical information team. The reporter is the patient.  A 90 year-old female patient received bnt162b2 (BNT162B2), administration date Apr2021 (Batch/Lot number: unknown) as dose 2, single for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose number:01, had the first dose of the Covid-19 vaccine in the first week of Mar2021 or Apr2021.), administration date: 2021, for covid-19 Immunization. The following information was reported: THINKING ABNORMAL (non-serious) with onset 2021, outcome "not recovered", described as "Having problems thinking straight"; CONFUSIONAL STATE (non-serious) with onset 2021, outcome "unknown", described as "Sometimes asked questions and doesn't know what to answer"; FATIGUE (non-serious) with onset 2021, outcome "unknown", described as "Devastating fatigue"; MEMORY IMPAIRMENT (non-serious) with onset 2021, outcome "unknown", described as "When speaking, in the middle of a sentence I can't remember the words I want to say /Keeps forgetting things".  Additional information: No PQC Present. She had the 2 doses of the Pfizer covid vaccine. She does not remember when she got the first or the second dose exactly, but she recalls having the second at the end of April. She says that after about week and a half later she started feeling that she is not thinking straight and it's getting worse. She cannot answer when she is called or answer questions, she loses what she is saying, etc. She says that she is also very fatigued and tired. She just wanted to know if this is something that has been reported.  She mentioned that she has not reported this before, but she has received to calls from this number today. She Explained that fatigue has been reported but not "not thinking straight". Referred some disclaimers from the CONS and recommended to consult her physician about this. The patient having problems thinking straight was reported as worsened. She got both doses of the Pfizer Covid-19 vaccine.  Caller reported that she doesn't remember exactly when she received the Covid-19 vaccine doses.  Caller reported that she is not at home, so she is not sure when this occurred. she thinks that she got the second dose of the Covid-19 vaccine at the end of Apr2021 and had the first dose of the Covid-19 vaccine in the first week of Mar2021 or Apr2021. Nurse reported that about a week and a half after she received the second dose of the Covid-19 vaccine, she began having problems thinking straight.  Nurse reported that her problems thinking straight are getting worse. She keeps forgetting things. when she is speaking, in the middle of a sentence she can't remember the words that she wants to say. Caller reported that she struggles with it and a minute or two later it comes to her. she also feels so fatigued and so tired.  Caller reported that the fatigue started about the same time as she began having difficulty thinking straight, a week and a half after she received the second dose of the Covid-19 vaccine. she was doing nothing but was so exhausted that she had to go sit in a chair. Caller reported that she just gets overwhelmed with fatigue. she received 2 calls from this number, and she doesn't know why she's having calls.  Caller reported that she called Pfizer yesterday and got tired of waiting.  Caller reported that a recording said that the lines were full and to leave a number to receive a call back.  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.