Injection site (Pfizer) became bright red within a half hour; Injection site (Pfizer) became swollen circle within a half hour; Felt hot; Prev dose brand=Moderna, Prev dose administration date=07Sep2022; product=COVID 19, brand=Pfizer, administration date=26Apr2023; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 69-year-old female patient (not pregnant) received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), on 26Apr2023 at 13:00 as dose 6 (booster), single (Lot number: GJ3268) at the age of 69 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "Pollen allergy" (unspecified if ongoing); "Perfume allergy" (unspecified if ongoing); "Allergy to molds" (unspecified if ongoing); "Allergy to animals" (unspecified if ongoing); "Fruit allergy (Melon, Banana)" (unspecified if ongoing); "Allergy to cosmetics" (unspecified if ongoing). Concomitant medication(s) included: ACETAMINOPHEN; FAMOTIDINE. Vaccination history included: BNT162b2 (Dose 1, Single, Lot Number: EI9266, Anatomical Location: Arm Left, Time of vaccine administration: 10:30 AM), administration date: 15Feb2021, for COVID-19 Immunization; BNT162b2 (Dose 2, Single, Lot Number: EN6206, Anatomical Location: Arm Left, Time of vaccine administration: 12:00 PM), administration date: 08Mar2021, for COVID-19 immunization; BNT162b2 (Dose 3 (Booster), Single, Lot Number: FF2588, Anatomical Location: Arm Left, Time of vaccine administration: 12:00 PM), administration date: 23Sep2021, for COVID-19 immunization; BNT162b2 (Dose 4 (Booster), Single, Lot Number: FK9895, Anatomical Location: Arm Left, Time of vaccine administration: 02:00 PM), administration date: 03Apr2022, for COVID-19 immunization; moderna (Dose 5 (Booster), Single, Lot Number: A57144B, Anatomical Location: Arm Left, Time of vaccine administration: 10:30 AM), administration date: 07Sep2022, for COVID-19 immunization. The following information was reported: INTERCHANGE OF VACCINE PRODUCTS (medically significant) with onset 26Apr2023 at 13:00, outcome "recovering", described as "Prev dose brand=Moderna, Prev dose administration date=07Sep2022; product=COVID 19, brand=Pfizer, administration date=26Apr2023"; FEELING HOT (medically significant) with onset 26Apr2023 at 13:15, outcome "recovering", described as "Felt hot"; VACCINATION SITE ERYTHEMA (medically significant) with onset 26Apr2023 at 13:15, outcome "recovering", described as "Injection site (Pfizer) became bright red within a half hour"; VACCINATION SITE SWELLING (medically significant) with onset 26Apr2023 at 13:15, outcome "recovering", described as "Injection site (Pfizer) became swollen circle within a half hour". Therapeutic measures were taken as a result of vaccination site erythema, vaccination site swelling, feeling hot with Benadryl pills. Clinical Course: It was reported that the Injection site (Pfizer) became bright red and swollen circle within a half hour. The diameter was almost 2 in. Felt hot. (The patient had had allergy shots as a teen, so patient felt it was clearly an allergic reaction but larger in size). The patient did not have other vaccine in four weeks. The patient did not have COVID prior vaccination or tested COVID post vaccination.