allergic reaction; arm blew up and it swelled up, became red and itchy; arm blew up and it swelled up; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team, Program ID: (159558). The reporter is the patient. A 45-year-old female patient (unknown if pregnant) received bnt162b2 omi xbb.1.5 (COMIRNATY (2023-2024 FORMULA)), on 20Sep2023 as dose 1, single (Lot number: HG4628) at the age of 45 years intramuscular for covid-19 immunisation. The patient's relevant medical history included: "shellfish allergy" (unspecified if ongoing); "seafood allergy" (unspecified if ongoing). The patient's concomitant medications were not reported. Vaccination history included: comirnaty (First Dose; Lot: ER8727), administration date: 23Mar2021, when the patient was 42-year-old, for COVID-19 immunisation; comirnaty (Second Dose; Lot: EW0162), administration date: 17Apr2021, when the patient was 42-year-old, for COVID-19 immunisation; moderna vaccine (Third Dose: Moderna Booster; Lot: Unknown), administration date: 10Nov2021, when the patient was 43-year-old, for COVID-19 immunisation; comirnaty (Fourth Dose; Lot: Unknown), administration date: 12Sep2022, when the patient was 44-year-old, for COVID-19 immunisation. The following information was reported: HYPERSENSITIVITY (non-serious) with onset 20Sep2023, outcome "not recovered", described as "allergic reaction"; PERIPHERAL SWELLING (non-serious) with onset 20Sep2023, outcome "recovering", described as "arm blew up and it swelled up"; ERYTHEMA (non-serious) with onset 20Sep2023, outcome "recovering", described as "arm blew up and it swelled up, became red and itchy". Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were taken as a result of hypersensitivity, erythema, peripheral swelling.  Additional information: Caller is asking if there are any seafood in the ingredients in the new vaccine because she had an allergic reaction. Stated she is allergic to shellfish, seafood.  She got the shot (2023-2024 comirnaty Covid 19 vaccine) yesterday and her arm 'blew up'. States that it swelled up, became red and itchy. Asking does the vaccine for 12 years and up contain seafood ingredients. Agent stated she addressed the caller's question about whether it contains those. Spoke per PMI/IAC "Comirnaty and/or Pfizer-BioNTech COVID-19 Vaccine (2023-2024 Formula) | COVID-19 Vaccine, mRNA does not contain Shellfish, Fish, and Products Thereof. Pfizer uses controlled manufacturing processes that meet quality standards of the pharmaceutical industry. However, Pfizer does not specifically manufacture or test Comirnaty and/or Pfizer-BioNTech COVID-19 Vaccine (2023-2024 Formula) | COVID-19 Vaccine, mRNA to be free of Shellfish, Fish, and Products Thereof. Therefore, cannot guarantee absence of trace amounts." Caller stated her arm is still swollen and still a little itchy but it has improved. Treatment: Cortisone and Zyrtec 10mg Doubled. She states she takes double Zyrtec when she has allergic reactions.  Caller states she does have an EpiPen, but she didn't have to use her EpiPen. Caller states at her last physical, all of her blood work was good.