Chemo-induced oral mucositis; she could not eat and ended up in the hospital; sepsis; hepatic encephalopathy; UTI; atrial fibrillation; non-occlusive thrombosis; thrombocytopenia; fluid in the lung; fluid in the thoracic cavity; hypernatremia; bacterial conjunctivitis; Breast cancer recurrence; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). A 70-year-old female patient (not pregnant) received BNT162b2 (BNT162B2), on 30Sep2021 as dose 3 (booster), single (Lot number: EW0150) at the age of 69 years intramuscular, in left arm for covid-19 immunisation. The patient's relevant medical history included: "cirrhosis" (unspecified if ongoing); "hepatic encephalopathy" (unspecified if ongoing); "edema" (unspecified if ongoing); "breast cancer", start date: Dec2001 (unspecified if ongoing). Concomitant medication(s) included: LACTULOSE; XIFAXAN; TORSEMIDE; FINASTERIDE; FAMOTIDINE; SPIRONOLACTONE; ALENDRONATE. Past drug history included: Codeine, reaction(s): "Known allergies: codeine". Vaccination history included: BNT162b2 (Dose number 2, Lot number EL9267, Intramuscular, Left arm), administration date: 12Feb2021, when the patient was 69-year-old, for Covid-19 immunization; BNT162b2 (Dose number 1, Lot number=EL3249, Intramuscular, Left arm), administration date: 22Jan2021, when the patient was 69-year-old, for Covid-19 immunization. The following information was reported: BREAST CANCER RECURRENT (hospitalization, disability) with onset Jan2022, outcome "not recovered", described as "Breast cancer recurrence"; MUCOSAL INFLAMMATION (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "Chemo-induced oral mucositis"; URINARY TRACT INFECTION (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "UTI"; ATRIAL FIBRILLATION (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered"; CONJUNCTIVITIS BACTERIAL (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "bacterial conjunctivitis"; PULMONARY OEDEMA (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "fluid in the lung"; PLEURAL EFFUSION (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "fluid in the thoracic cavity"; HEPATIC ENCEPHALOPATHY (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered"; HYPERNATRAEMIA (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "hypernatremia"; THROMBOSIS (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "non-occlusive thrombosis"; SEPSIS (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered"; FEEDING DISORDER (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered", described as "she could not eat and ended up in the hospital"; THROMBOCYTOPENIA (hospitalization, disability, life threatening) with onset 04Apr2022, outcome "not recovered". The patient was hospitalized for mucosal inflammation, feeding disorder, sepsis, hepatic encephalopathy, urinary tract infection, atrial fibrillation, thrombosis, thrombocytopenia, pulmonary oedema, pleural effusion, hypernatraemia, conjunctivitis bacterial (hospitalization duration: 44 day(s)); for breast cancer recurrent (hospitalization duration: 1 day(s)). The event "breast cancer recurrence" required physician office visit. The events "chemo-induced oral mucositis", "she could not eat and ended up in the hospital", "sepsis", "hepatic encephalopathy", "uti", "atrial fibrillation" and "non-occlusive thrombosis" required physician office visit and emergency room visit. The patient underwent the following laboratory tests and procedures: SARS-CoV-2 test: (12Jan2022) Negative, notes: Nasal Swab. Therapeutic measures were taken as a result of mucosal inflammation, feeding disorder, sepsis, hepatic encephalopathy, urinary tract infection, atrial fibrillation, thrombosis, thrombocytopenia, pulmonary oedema, pleural effusion, hypernatraemia, conjunctivitis bacterial, breast cancer recurrent.  Additional information: adverse events treatment included Magic mouthwash, lidocaine, dexamethasone, platelets, furosemide, Lovonox, antibiotics, tube feeds.Breast cancer recurrence treatment included Single mastectomy, chemo.