I couldn't find my way home on a walk the block; Was not able to walk/Felt like she was walking through mud; I got double vision; brain fog; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 65-year-old female patient received bnt162b2 (BNT162B2), on 21Jul2022 as dose 4 (booster), single (Lot number: Fn2908) at the age of 64 years, in right arm for covid-19 immunisation. The patient's relevant medical history included: "Bumped on head", start date: Jul2022 (unspecified if ongoing), notes: maybe a few years ago. Concomitant medication(s) included: FLINTSTONES MULTIPLE VITAMINS [VITAMINS NOS]; VITAMINE C. Vaccination history included: bnt162b2 (1st dose, Anatomical Site of injection: Unknown, Batch/Lot number: appears to be, EJ1686), administration date: 12Mar2021, when the patient was 62-year-old, for COVID-19 immunization; bnt162b2 (2nd dose, Anatomical Site of injection: Unknown. Thinks she always gets in right arm, gets flu shots in right arm. , Batch/Lot number: EP6955), administration date: 02Apr2021, when the patient was 62-year-old, for COVID-19 immunization; bnt162b2 (3rd dose, Batch/Lot number: FE2590), administration date: 11Nov2021, when the patient was 63-year-old, for COVID-19 immunization, reaction(s): "developed brain fog". The following information was reported: DIPLOPIA (non-serious) with onset 21Jul2022, outcome "unknown", described as "I got double vision"; BRAIN FOG (non-serious) with onset 21Jul2022, outcome "recovered" (24Jul2022); DISORIENTATION (non-serious) with onset 23Jul2022, outcome "unknown", described as "I couldn't find my way home on a walk the block"; GAIT DISTURBANCE (non-serious) with onset 23Jul2022, outcome "unknown", described as "Was not able to walk/Felt like she was walking through mud". Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were not taken as a result of brain fog, disorientation, gait disturbance, diplopia. Additional information: Caller mentions that she already spoke with someone else from Medical Information department last year regarding the 3rd and 4th Pfizer COVID vaccines. Caller added, "my fourth dose, I not only got brain fog where I couldn't find my way home on a walk the block, this is like day 2 brain fog, I had it for three days, but also I got double vision on my fourth dose and that was last July." Caller stated that she really want to have a children's dose. Caller states she weighs 110 pounds, totally healthy, no medicines, 65 years, freely active, not immunocompromised. Caller states that she is going on a trip and she is not getting the vaccine as she got scared of the brain fog and the double vision. She will only receive the vaccine if it is the children's dose. Caller states when she spoke with someone from this line a year ago and was informed that "After and evaluation it is ultimately up to my health care provider's discretion." Caller states her physician would like to give her the half dose however it is against the rules. Caller would like to know if she could receive half of the dose of the COMIRNATY 2023-2024 formula. Provided that caller received 4th dose Pfizer Covid vaccine. Developed some brain fog, wasn't able to walk. Had that for 3 days. Also, had double vision last July. Weighs around 110 pounds, is extremely active, not really immunocompromised. With third dose Pfizer Covid vaccine last year, developed brain fog, that was reported. Fourth dose, where she developed brain fog and double vision, not sure if that was reported. Clarified, today is first day reporting brain fog and not being able to walk, after fourth dose Covid vaccine. Clarified, double vision occurred last Jul2022. Clarified, caller is respiratory therapist, for about 15 years, was also in nursing also. Clarified, she was never licensed as nurse, physician or pharmacist. Developed some brain fog: Got fourth dose, 21Jul2022. Started shortly after that, brain fog lasted 3 days. Would say, it started the next day, after the vaccine on 21Jul2022, it started, within 24 hours. Wasn't able to walk: Started on third day. Was going for walk, thought maybe she could walk and get rid of this, by walking around. Felt like she was walking through mud, got 3/4 way around block, just got over whelmed with brain fog. For a moment, wasn't sure where she was, looked over, could see house. Was not able to walk, would say, once she got home, didn't go anywhere. Can't say, when it was, was in fog but, knew she could function, could cook dinner, do everything she needed to do. It was peaked at that walk, then after, didn't notice anything as intense. Double vision: Clarified, this started same time as brain fog. Lasted maybe, a half a day. Is familiar with that because, she bumped head maybe a few years ago. Never had concussion before, understands what double vision is, husband is ER physician. It was vertical double vision. Horizontal double vision is more eye function. Treatment: No, is a person who does not like to take medication. Maybe the first day, if she had fever or chills, would be the only time she would take something. Maybe day 1, she may have had a little fever, may have taken something if she was having symptoms. Would have taken Advil. Indication: Didn't want to take it because, previous time, was asking for half dose, wasn't confirmed she could do half dose or, children's dose. Didn't want to take because of brain fog of third dose. Husband told her she was going to get long Covid, did not want that. Put the fear in her to get it done. Believes in vaccines, don't think she is an anti vaxxer.