Dizziness; Hypotension; Myalgias; Arthralgias; Severe chills; Muscle cramping; Leukopenia; Hypokalemia; Fever; Abdominal pain; Nausea; Vomiting; Severe adverse reaction to 2nd dose of Moderna COVID-19 vaccine; Fatigue;  This is a non-interventional study report (Post Authorization Safety Study) received from a contactable reporter(s) (Other HCP) for protocol.  A 43-year-old female patient received BNT162b2 (reported as COVID-19 vaccine, manufacturer not specified), on 23Dec2020 as dose 1, single intramuscular for covid-19 immunisation (reported as covid-19 prophylaxis). The patient's relevant medical history included: "Depression" (unspecified if ongoing); "Restless leg syndrome" (unspecified if ongoing); "Cervical cancer" (unspecified if ongoing); "Partial Hysterectomy" (unspecified if ongoing); "Acid Reflux" (unspecified if ongoing); "GERD (gastroesophageal reflux disease)" (unspecified if ongoing); "Gastric restriction surgery/bariatric surgery", start date: 21Aug2018, stop date: 21Aug2018; "Status post biliopancreatic diversion with duodenal switch" (unspecified if ongoing); "Loose stools since bariatric surgery" (unspecified if ongoing); "PTSD (Post traumatic stress disorder)" (unspecified if ongoing); "Sleep Apnea" (unspecified if ongoing); "Latex (itching)" (unspecified if ongoing). Concomitant medication(s) included: INSULIN subcutaneous (ongoing); CYMBALTA oral (ongoing); PROAIR HFA resp inhalation taken for dyspnoea (ongoing); SAXENDA (ongoing); KLONOPIN oral taken for anxiety (ongoing); BENADRYL oral taken for pruritus (ongoing); NEURONTIN oral taken for restless legs syndrome (ongoing); OMEPRAZOLE oral (ongoing). Past drug history included: Capsaicin, reaction(s): "anaphylaxis"; Phentermine, reaction(s): "anaphylaxis"; Phentermine, reaction(s): "hives"; Adhesive tape - silicones, reaction(s): "rash"; Bupropion hcl, reaction(s): "hives". The following information was reported: FATIGUE (hospitalization) with onset 20Jan2021; IMMUNISATION REACTION (hospitalization) with onset 20Jan2021, described as "Severe adverse reaction to 2nd dose of Moderna COVID-19 vaccine"; ABDOMINAL PAIN (hospitalization) with onset 21Jan2021; PYREXIA (hospitalization) with onset 21Jan2021, described as "Fever"; NAUSEA (hospitalization) with onset 21Jan2021; VOMITING (hospitalization) with onset 21Jan2021; ARTHRALGIA (hospitalization) with onset 22Jan2021, described as "Arthralgias"; HYPOKALAEMIA (hospitalization) with onset 22Jan2021, described as "Hypokalemia"; LEUKOPENIA (hospitalization) with onset 22Jan2021; MUSCLE SPASMS (hospitalization) with onset 22Jan2021, described as "Muscle cramping"; MYALGIA (hospitalization) with onset 22Jan2021, described as "Myalgias"; CHILLS (hospitalization) with onset 22Jan2021, described as "Severe chills"; DIZZINESS (hospitalization) with onset 22Jan2022; HYPOTENSION (hospitalization) with onset 22Jan2022. Clinical course: On 20Jan2021, the participant received her second dose of Covid-19 vaccine, reported as the Moderna vaccine. One year later, on 20Jan2022, the participant received an additional vaccine dose (manufacturer not identified). On 22Jan2021, two days after having received her second vaccination, the participant presented to the hospital with complaints of nausea, vomiting, fever, and abdominal pain. Subsequently, she was admitted into the hospital for symptomatic management. The participant reported that after having received the second vaccine dose, she experienced fatigue; however, on 21Jan2021, the day after her second vaccination, she became febrile at work in the early afternoon. She also began experiencing bilateral abdominal pain that started on her sides and wrapped from her lower back around to the front of her abdomen. The abdominal pain came in 'waves' and led to dry heaves, nausea and vomiting. The participant reported that she experienced approximately ten episodes of dry heaving and non bilious vomiting. She was unable to keep any food, drink or medication down. The participant reported that overnight she developed bilateral myalgias and arthalgias throughout her upper and lower extremities. In addition, she experienced severe chills that led to muscle cramping. She complained of dizziness with standing and sitting but denied shortness of breath, chest pain, headaches, dysuria, and hematuria. At the time of admission, the participant reported that for the past couple of weeks she had noted abdominal discomfort. She attributed this to increased stress at work for the previous month with a resulting increase in carbohydrate diet She explained that due to her bariatric surgery, she normally avoided heavy carbohydrate foods. She endorsed frequent non-bloody bowel movements and diarrhea; however, she noted that since her bariatric surgery she experienced looses tools and had no recent change in her bowel habits. Upon physical examination, the participant was alert, oriented and in no acute distress. Her lungs were clear bilaterally to auscultation and she exhibited normal respiratory effort. Her heartrate was normal with a regular rhythm. Her skin was warm and well perfused. Her abdomen was non-distended with normal bowel sounds; it was tender to deep palpation bilaterally. Vital signs included: temperature 37.1 degrees Celsius, heart rate 50 beats per minute, respirations 16 breaths per minute, blood pressure 92/59 mmHg and oxygen saturation 97 %. A peripheral intravenous line was inserted and she was admitted for further management. Laboratory and diagnostic tests were obtained (see results below). During admission she received paracetamol (TYLENOL) (also reported as ACETAMINOPHEN), ondansetron (ZOFRAN), and 40 mEq of potassium chloride. She received four liters of fluid during admission. On 23Jan2021, the participant was discharged. Physical examination at time of discharge revealed her to be alert, oriented and in no distress. She remained afebrile and vital signs included: pulse 58 beats per minute, respiratory rate 20 breaths per minute, left upper arm blood pressure (sitting position) 115/74 mmHg and oxygen saturation 97 %. Her lungs were clear bilaterally, heart rate was normal with regular rhythm; bowel sounds were normal; no abdominal distention. No epigastric tenderness. Her skin was warm and well perfused. The patient underwent the following laboratory tests and procedures: Alanine aminotransferase (14-54): (22Jan2021) 31 IU/l; Aspartate aminotransferase (15-41): (22Jan2021) 26 IU/l; Blood alkaline phosphatase (24-110): (22Jan2021) 57 IU/l; Blood bilirubin (0.4-1.5): (22Jan2021) 0.6 mg/dl; Blood calcium (8.7-10.2): (22Jan2021) 8.0 mg/dl; (23Jan2022) 7.6 mg/dl; Blood chloride (98-108): (22Jan2021) 109 mmol/L; (23Jan2022) 112 mmol/L; Blood creatine phosphokinase (30-220): (22Jan2021) 42 IU/l; Blood creatinine (0.4-1.0): (22Jan2021) 0.7 mg/dl; (23Jan2022) 0.6 mg/dl; Blood culture: (22Jan2021) No grow th detected at 48 hours, notes: and after 5 days (as of 27Jan2021); Blood glucose (70-140): (22Jan2021) 115 mg/dl; (23Jan2022) 97 mg/dl; Blood lactic acid (0.6-2.2): (23Jan2022) 1.0 mmol/L; Blood potassium (3.5-5.0): (22Jan2021) 3.3 mmol/L; (23Jan2022) 4.4 mmol/L; Blood sodium (135-145): (22Jan2021) 137 mmol/L; (23Jan2022) 140 mmol/L; Blood urea (7-20): (22Jan2021) 11 mg/dl; (23Jan2022) 14 mg/dl; Carbon dioxide (21-30): (22Jan2021) 23 mmol/L; (23Jan2022) 25 mmol/L; Chest X-ray: (22Jan2021) normal; Computerised tomogram abdomen: (22Jan2021) Status post cholecystectomy, notes: prior upper abdominal bariatric surgery noted. No evidence of bowel dilation. No free air. Liver was homogeneous; Common bile duct measured 9 mm, upper limits of normal for cholecystectomy spleen, kidneys and adrenals unremarkable. Modest pelvic fluid, nonspecific given the presence of a degenerating left ovarian follicle and several small right ovarian cysts; uterus surgically absent. Appendix surgically absent; Computerised tomogram pelvis: (22Jan2021) Status post cholecystectomy,, notes: prior upper abdominal bariatric surgery noted. No evidence of bowel dilation. No free air. Liver was homogeneous; Common bile duct measured 9 mm, upper limits of normal for cholecystectomy spleen, kidneys and adrenals unremarkable. Modest pelvic fluid, nonspecific given the presence of a degenerating left ovarian follicle and several small right ovarian cysts; uterus surgically absent. Appendix surgically absent; Culture urine: (22Jan2021) Mixed flora, probable contamination; Cytomegalovirus test: (22Jan2021) negative; Electrocardiogram: (23Jan2022) Marked sinus bradycardia, abnormal ECG, notes: Vent rate: 44 beats per minute (BPM); PR interval: 186 ms; QRS duration: 92 ms; QT/QTc 488/417; P-R-T axes: 27-57-40; Haematocrit (35.0-45): (22Jan2021) 31.3 %; (23Jan2022) 29.0 %; Haemoglobin (12.0-15.5): (22Jan2021) 10.5 g/dl; (23Jan2022) 9.4 g/dl; Influenza A virus test: (22Jan2021) not detected; Influenza B virus test: (22Jan2021) not detected; Mononucleosis heterophile test: (22Jan2021) negative; Platelet count (150-450): (22Jan2021) 164 x10 9/l; (23Jan2022) 135 x10 9/l; Respiratory syncytial virus test: (22Jan2021) not detected; SARS-CoV-2 test: (22Jan2021) not detected, notes: Source: nasopharyngeal swab; nasal wash; Ultrasound pelvis: (22Jan2021) No definitive abnormalities of ovaries or adnexa., notes: No definite mass lesion or abnormal fluid collection of the pelvis. Normal Doppler study of the ovaries; Urine analysis: (22Jan2021) Color: Yellow; Clarity: Slight cloudy;, notes: Specific gravity: 1.025; Protein: negative; Glucose: negative; Ketones: Negative; Blood: Negative; Leukocytes: Negative; Bilirubin: Negative; Urobilinogen: 0.2; White blood cell count (3.2-9.8): (22Jan2021) 1.9 x10 9/l; (23Jan2022) 3.9 x10 9/l. Physician assessment: "Likely an immune response to COVID vaccine. Patient appeared to have a severe adverse reaction to second dose of Modema COVID-19 vaccine. Recommend attention to adverse reactions with future vaccines." Diagnosis/clinical impression: Abdominal pain; generalized fever, unspecified, unspecified hypotension. The action taken in response to the event for BNT162b2 was not applicable. The outcome of the events "fatigue", "fever", "abdominal pain", "nausea", "vomiting", "myalgias", "arthralgias", "severe chills", "muscle cramping", and "dizziness" was unknown. The outcome of the events "severe adverse reaction to 2nd dose of moderna covid-19 vaccine" and "hypotension" was recovering. The outcome of the events "leukopenia" and "hypokalemia" was recovered on 23Jan2021.   The reporter considered "severe adverse reaction to 2nd dose of moderna covid-19 vaccine", "fatigue", "fever", "abdominal pain", "nausea", "vomiting", "myalgias", "arthralgias", "severe chills", "muscle cramping", "dizziness", "hypotension", "leukopenia" and "hypokalemia" related to BNT162b2, but unrelated to concomitant drugs.; Sender's Comments: Based on the information in the case report, a possible causal relationship between the reported events and the suspect drug BNT162B2 cannot be completely excluded.  The impact of this report on the benefit/risk profile of the Pfizer drug is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.