heart fluttering; fatigue; fever; weakness; very shaky; had to concentrate to be able to breath; This is a spontaneous report received from a Consumer or other non HCP from medical information team. A 75-year-old female patient received BNT162b2 omicron (kp.2) (COMIRNATY (2024-2025 FORMULA)), as dose 1, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient’s relevant medical history included: “Stage III Endometrial cancer” (not ongoing), notes: she beat it, she’s in health now. The patient’s concomitant medications were not reported. Vaccination history included: Bnt162b2 (DOSE 1, SINGLE), for Covid-19 Immunization; Bnt162b2 (DOSE 2, SINGLE), for Covid-19 Immunization; Comirnaty (2023-2024 formula) (DOSE 3 (BOOSTER), SINGLE), administration date: Oct2023, for Covid-19 Immunization, reaction(s): “severe reaction”. The following information was reported: CARDIAC FLUTTER (medically significant), 10 hrs after the suspect product(s) administration, outcome “not recovered”, described as “heart fluttering”; FATIGUE (non-serious), 10 hrs after the suspect product(s) administration, outcome “not recovered”; PYREXIA (non-serious), outcome “not recovered”, described as “fever”; ASTHENIA (non-serious), 10 hrs after the suspect product(s) administration, outcome “not recovered”, described as “weakness”; TREMOR (non-serious), 10 hrs after the suspect product(s) administration, outcome “unknown”, described as “very shaky”; DYSPNOEA (non-serious), 10 hrs after the suspect product(s) administration, outcome “unknown”, described as “had to concentrate to be able to breath”. Clinical course: Caller had all her Pfizer COVID-19 doses, first, second, third and the most recent one, but on the last one, she started experiencing fever, weakness, heart fluttering, fatigue, and she’s wondering what to do now. She wanted to know whether to get the new vaccine or not. She mentioned she’s afraid to get another vaccination, but she’s also afraid of getting covid and not surviving. She doesn’t know what to do. She added that she’s 75 years old, and not in an age to fight. She also had a cancer diagnosis few years ago, it was Stage III Endometrial, and she beat it, she’s in health now, but her body is been through a lot. She mentioned her reaction was so bad, she really thought she was going to die. She stated that the fatigue went through weeks and weeks, and she went to the ER several times, and nobody knew what to do. Caller mentioned her previous dose was about a year ago, Oct2023, she mentioned it might have been the “bi-variant”. Caller also wanted to know if having a previous history of side effects to the other Pfizer COVID-19 Vaccine formulations would cause her to get a reaction again. Caller then spoke about “preveset” or “prevesid”, which is a medication given by doctors to make a milder case of covid if you take this medication within the first days of getting COVID, but she added her doctor told her that their site is not using that medication as it has too many complications, too many reactions. Caller finally stated that she will either try to get lucky, or maybe switch to Moderna to avoid reaction with our vaccine again. Consumer stated, “So, I had a several of the Pfizer COVID shot (Later clarified as Pfizer COVID-19 Shot) the 1st, the 2nd, the 3rd and the last one I had, I had terrible reaction from it that lasted, the most severe reaction was, I had it 11 O’clock in the morning and at 09:30 that evening the reaction was extremely severe, I suddenly got very weak, very shaky, my heart was kind of fluttering, I had to concentrate to be able to breath and I had extreme fatigue for weeks and weeks afterwards. So, I am wondering, what do I do now to not die from COVID because I am worried about it.” No follow-up attempts are possible. Batch/lot number is not provided, and it cannot be obtained.