hot/ It was really hot, but it was going down a lot; she could hardly use her arm; got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red and she didn't' know how much longer it was going to last. She had soreness and redness; redness/ got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red; swollen up/ got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  An 89-year-old female patient received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), on 14Sep2022 as dose 4 (booster), single (Batch/Lot number: unknown) at the age of 89 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "diabetic", start date: 2007 (unspecified if ongoing), notes: thought she was diagnosed in 2007; "high blood pressure", start date: 2007 (unspecified if ongoing), notes: diagnosed soon after diabetes within the same year; "Cholesterol" (unspecified if ongoing); "heartburn" (unspecified if ongoing); "indigestion" (unspecified if ongoing); "cataracts" (unspecified if ongoing); "glaucoma" (unspecified if ongoing). Concomitant medication(s) included: FAMOTIDINE taken for dyspepsia, dyspepsia (ongoing); ROSUVASTATIN (ongoing); METOPROLOL (ongoing); VALSARTAN (ongoing); TORADOL taken for pain (ongoing). Vaccination history included: BNT162b2 (Dose 1, Lot number: EL9261), administration date: 25Jan2021, when the patient was 87-year-old, for Covid-19 Immunisation; BNT162b2 (Dose 2, Lot number: EC9267), administration date: 15Feb2021, when the patient was 87-year-old, for Covid-19 Immunisation; BNT162b2 (Dose 3, Lot number: FF8841), administration date: 12Oct2021, when the patient was 88-year-old, for Covid-19 Immunisation. The following information was reported: PAIN IN EXTREMITY (non-serious) with onset 14Sep2022, outcome "recovered", described as "got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red and she didn't' know how much longer it was going to last. She had soreness and redness"; ERYTHEMA (non-serious) with onset 14Sep2022, outcome "recovering", described as "redness/ got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red"; PERIPHERAL SWELLING (non-serious) with onset 14Sep2022, outcome "recovering", described as "swollen up/ got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red"; FEELING HOT (non-serious), outcome "recovering", described as "hot/ It was really hot, but it was going down a lot"; VACCINATION SITE MOVEMENT IMPAIRMENT (non-serious), outcome "unknown", described as "she could hardly use her arm".  Additional information: Reason for no lot number of Pfizer BioNtech Bivalent Diluent Booster was stated as unable to locate or read lot number on Pfizer trade packaging. Indication for suspect product reported as "was told to get the vaccine". She was taking Vitamins for unspecified indication and Eye drops for cataracts and glaucoma. Caller stated she got the Pfizer booster on her left arm on 14Sep2022, and it swelled up and turned red and she didn't' know how much longer it was going to last. She had soreness and redness, no reaction with the first one. HCP: whole health. Stated she showed it to her doctor and was told if she was concerned then to report it. She had an appointment on 19Sep2022 and that is when her doctor said if it didn't clear to report it. Caller stated that it was hot. She started to notice it was red. Her sister got one and she called her and asked if she had a sore and red arm, and she said no. Caller stated it has cleared up a lot since yesterday. It was not as sore and hardly warm. It wasn't swollen up as it was, but she didn't know if it was supposed to do that. Asked if it last this long, it was much better. Caller states she wasn't sick, she didn't feel bad. she was told to just check the redness every morning and call and report it. It was not as hot anymore. It was really hot, but it was going down a lot and she could hardly use her arm. It swollen up and got hot and she has just been watching it but wanted to report it. Investigations included none.  The information on the batch/lot number for BNT162b2, BNT162b2 omi ba.4-5 has been requested and will be submitted if and when received.