a 2 year long explosive diarrhea episode with diarrhea after eating; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 66-year-old female patient received BNT162b2 (BNT162B2), on 06Apr2022 as dose 4 (booster), single (Lot number: FP4554) at the age of 65 years, in right arm for covid-19 immunisation. The patient's relevant medical history included: "Hypothyroid" (ongoing); "Food skin test: Stringbeans/Greenbeans" (unspecified if ongoing), notes: Food skin test: Stringbeans/Greenbeans, RXN: +/- (Questionable response); "Food skin test: Histamine" (unspecified if ongoing), notes: Food skin test: Histamine, RXN: 2 (moderate allergic) - 3 (Highly allergic). Concomitant medication(s) included: NP THYROID oral taken for hypothyroidism (ongoing). Vaccination history included: BNT162b2 (DOSE 1, SINGLE, Anatomical Site of injection: Right Arm, Batch/Lot Number: EP7534, EXP: 30Jul2021), administration date: 20Mar2021, when the patient was 64-year-old, for COVID-19 Immunization; BNT162b2 (DOSE 2, SINGLE, Anatomical Site of injection: Right Arm, Batch/Lot Number: EW0162, EXP: 31Jul2021), administration date: 10Apr2021, when the patient was 64-year-old, for COVID-19 Immunization, reaction(s): "Diarrhea", "Granuloma annulare generalized all over arms, hands, legs, and feet"; BNT162b2 (DOSE 3 (BOOSTER), SINGLE, Anatomical Site of injection: Right Arm, Batch/Lot Number: FF2593), administration date: 01Nov2021, when the patient was 65-year-old, for COVID-19 Immunization, reaction(s): "Diarrhea". The following information was reported: DIARRHOEA (medically significant), outcome "unknown", described as "a 2 year long explosive diarrhea episode with diarrhea after eating". The patient underwent the following laboratory tests and procedures: Blood immunoglobulin A (87-352): (unspecified date) 123 mg/dl; Blood test: (unspecified date) Nothing showed; Clostridium test: (14Sep2022) Negative, notes: at 09:44AM; Ref range & Units: Negative; Computerised tomogram intestine: (unspecified date) CT Enterography looks fine., notes: CT Enterography looks fine. The small and large intestine looks normal without any sign of  inflammatory change, narrowing, polyps or masses. You had some gallstones without any changes in the gallbladder wall itself. The little possible kidney cysts are not of concern; Endomysial Antibody IgA: (unspecified date) Negative; (14Sep2022) No ova, cysts, or parasites seen, notes: One negative specimen does not rule out the possibility of parasite infections; Pancreatic elastase, fecal (normal low range 200): (14Sep2022) >500, notes: at 09:44AM; Ref range & Units: >200 ug Elast./g; t-Transglutaminase (tTG) IgA (0-3): (unspecified date) <2 IU/ml; Stool analysis: (25Aug2022) unknown results, notes: stool studies for Clostridium difficile PCR, Ova and parasites and pancreatic elastase; (14Sep2022) Negative, notes: The stool studies were negative or normal (pancreatic function) including Pancreatic Elastase, Fecal; C difficile PCR and Ova and Parasites, Conc-Smear#1; Urine analysis: (unspecified date) Unknown Result. Therapeutic measures were taken as a result of diarrhoea.  Clinical course: Within 4-5 days of receiving the second vaccine on 10Apr2021, patient began a 2 year long explosive diarrhea episode with diarrhea after eating from morning until 3 pm every day [only ate breakfast] which caused her to become homebound. Patient had stool tests, blood tests, treatment with antibiotics- nothing showed upon tests, treatment did not work. Clinical History was chronic diarrhea. The lab studies ordered on 25Aug2022, and the labs ordered under ICD- # were stool studies for Clostridium difficile PCR, Ova and parasites and pancreatic elastase. Vaccination Facility type was public health clinic. No Prior Vaccinations (within 4 weeks). No Specific Relevant test for Thromboembolic with Thrombocytopenia. Patient received booster dose (other) Pfizer Bivalent Lot# GH9702 on 14Sep2022 for covid-19 immunisation. As per physician, the date of visit was 17Nov2022, the patient under physician care at medical center for management of chronic intractable diarrhea. She had been having many lab studies including stool, urine, and blood testing to try to ascertain the cause of her unrelenting diarrhea. As yet, don't have a diagnosis so the physician was really trying to cover all bases to look for a cause.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202300091602 same patient/reporter, different vaccine dose;US-PFIZER INC-PV202300104357 same patient/reporter, different vaccine dose;