The flu side looks a little more hard and bumpy under the skin; Big round red rash around both injection sites/Both are 3 inch diameter; Felt a big welt on her shoulder; felt a big welt on her shoulder; Yesterday, patient was feeling sick and not quite feeling well; Is big red around site and it was warm; His wife felt a little sick yesterday; She had a low fever; Her cheeks were a little red; Both arms have a big round rash; Feel heat radiating; Got the flu shot in the right arm and COVID booster in the left arm; Got the flu shot in the right arm and COVID booster in the left arm.; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team.  A 58-year-old female patient received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), on 25Oct2022 as dose 4 (booster), single (Lot number: GJ5342) at the age of 58 years, in left arm for covid-19 immunisation; influenza vaccine (INFLUENZA VACCINE), on 25Oct2022 as dose number unknown, single (Batch/Lot number: unknown), in right arm for immunisation. The patient's relevant medical history included: "Crohn's disease" (unspecified if ongoing); "Estrogen repacent" (ongoing), notes: Estrogen repacent. Concomitant medication(s) included: COMBIPATCH taken for oestrogen replacement therapy (ongoing). Vaccination history included: BNT162b2 (1st dose, Batch/Lot number: EW0153, NDC, EXP: Unknown), administration date: 07Apr2021, when the patient was 56-year-old, for COVID-19 immunization; BNT162b2 (2nd dose, Batch/Lot number: ER8736, NDC, EXP: Unknown), administration date: 07May2021, when the patient was 56-year-old, for COVID-19 immunization; BNT162b2 (3rd dose, Batch/Lot number: 33038D, NDC, EXP: Unknown), administration date: 07Dec2021, when the patient was 57-year-old, for COVID-19 immunization. The following information was reported: OFF LABEL USE (non-serious) with onset 25Oct2022, outcome "unknown", described as "Got the flu shot in the right arm and COVID booster in the left arm"; PRODUCT USE ISSUE (non-serious) with onset 25Oct2022, outcome "unknown", described as "Got the flu shot in the right arm and COVID booster in the left arm."; RASH (non-serious) with onset 26Oct2022, outcome "unknown", described as "Both arms have a big round rash"; FEELING HOT (non-serious) with onset 26Oct2022, outcome "unknown", described as "Feel heat radiating"; ERYTHEMA (non-serious) with onset 26Oct2022, outcome "not recovered", described as "Her cheeks were a little red"; ILLNESS (non-serious) with onset 26Oct2022, outcome "recovered" (27Oct2022), described as "His wife felt a little sick yesterday"; VACCINATION SITE WARMTH (non-serious) with onset 26Oct2022, outcome "unknown", described as "Is big red around site and it was warm"; PYREXIA (non-serious) with onset 26Oct2022, outcome "recovering", described as "She had a low fever"; MALAISE (non-serious) with onset 26Oct2022, outcome "recovering", described as "Yesterday, patient was feeling sick and not quite feeling well"; URTICARIA (non-serious) with onset 27Oct2022, outcome "unknown", described as "Felt a big welt on her shoulder"; MUSCULOSKELETAL DISCOMFORT (non-serious) with onset 27Oct2022, outcome "unknown", described as "felt a big welt on her shoulder"; VACCINATION SITE MASS (non-serious), outcome "unknown", described as "The flu side looks a little more hard and bumpy under the skin"; VACCINATION SITE RASH (non-serious), outcome "unknown", described as "Big round red rash around both injection sites/Both are 3 inch diameter". Therapeutic measures were taken as a result of pyrexia.  Additional information: The caller was calling about his wife who received the Pfizer BioNTech COVID-19 Vaccine Bivalent booster for adults and the Flu vaccine on the same day on opposite arms. Both arms have a big round rash and he is wanting to know why both would both arms have that same reaction? They are 3 inch across, big red round rash and you can feel heat radiating. He stated the flu side looks a little more hard and bumpy under the skin. The other side is same diameter rash around the injection site. The caller and his wife both had both vaccines 2 days ago on the 25. He stated he got it at the same time as her and he seems fine. His wife felt a little sick yesterday and he noticed her cheeks were a little red and she had a low grade fever. She took an ibuprofen last night when she was running the low grade fever and went to bed and woke up fine except for the round rashes. He stated he finds it odd that she has the same rash on each arm and you would think if it was from the COVID it wouldn't be around each injection site since the COVID was only in one arm. He stated he isn't sure what brand of flu shot they got. This was the first time they had the newer variant booster shots. They had previous ones (vaccines) and finds it odd they (both arms) look the same almost and are red. He stated if it was the COVID shot it would just be on one arm. He stated he hopes they didn't inject her with something else because he finds it odd that both arms were like this. He is not sure if they would have made a mistake. He wanted to know why both arms would look the same and have this same reaction? Caller and wife both got the COVID vaccine 2 days ago and got the flu shot. It was the COVID booster, the new booster. Caller and wife went to pharmacy 2 days ago and got the flu shot in the right arm and COVID booster in the left arm. The following day, both of caller's arms are slightly sore but he had no problems. Patient has a big round red rash around both injection sites, for both the flu shot in the left and COVID shot in the right. Both are 3 inch diameter. Is big red around site and it was warm. Reported this to the pharmacy and they said ok. It was not the high dose flu shot, it was the regular. They are both 3 inch in diameter, round red and warm to the touch. Patient felt a little sick yesterday and face was a little red and felt a little sick. Went to sleep last night and woke up today, and felt a big welt on her shoulder. Caller states he did not have any adverse reaction like this. Yesterday, patient was feeling sick and not quite feeling well. Big red round rash: first noticed yesterday, 26Oct2022. Outcome: Is a pretty good size. Right arm looked a little hard and a little red. Clarified that patient had flu shot in right arm and COVID shot in the left arm. Both arms have the same rash but left arm not as hard as right arm. They are both the same diameter circle, like 3 inches across and bright red. The circle of red is slightly better on the right arm but still really hard. Does not feel sick today. Treatment: Is on a hormone patch that she started about a week ago. Clarified that caller had been taking this and did not take it specially for this rash. Patient did take 1 Ibuprofen yesterday, which helped with the slight fever she had. Yesterday, patient was not feeling well and took Ibuprofen that helped a little with the fever. Flu Shot is not sure if the Flu shot was Pfizer or not. Caller had the same shots as patient but, did not have the rash. is nothing personal but the pharmacy seems to have really went downhill. Hopes nothing was contaminated when they gave the injection. Does not feel it was the COVID shot. Both arms, where the injection was were affected. Unless, the pharmacy contaminated the doses and mixed them up some how. Is almost like both arms got the same reaction. The flu shot arm is a little harder but both had the same circle and were both warm and red. No family medical history relevant to adverse events.