diffuse SMV thrombosis; extension of thrombus into the main and left hepatic portal veins; intermittent lower abdominal pain radiating laterally in a band-like distribution with pressure and bloating sensation; intermittent lower abdominal pain radiating laterally in a band-like distribution with pressure and bloating sensation; This is a literature report for the following literature source.  A 67 year-old male patient received bnt162b2 (BNT162B2) (Batch/Lot number: unknown) as dose 2, single for covid-19 immunisation. Relevant medical history included: "Hyperlipidemia" (unspecified if ongoing); "Coronary artery disease" (unspecified if ongoing). The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose 1), for covid-19 immunisation. The following information was reported: MESENTERIC VEIN THROMBOSIS (hospitalization, medically significant), outcome "unknown", described as "diffuse SMV thrombosis"; PORTAL VEIN THROMBOSIS (hospitalization, medically significant), outcome "unknown", described as "extension of thrombus into the main and left hepatic portal veins"; ABDOMINAL PAIN LOWER (non-serious), ABDOMINAL DISTENSION (non-serious), outcome "unknown" and all described as "intermittent lower abdominal pain radiating laterally in a band-like distribution with pressure and bloating sensation". The events "diffuse smv thrombosis", "extension of thrombus into the main and left hepatic portal veins", "intermittent lower abdominal pain radiating laterally in a band-like distribution with pressure and bloating sensation" and "intermittent lower abdominal pain radiating laterally in a band-like distribution with pressure and bloating sensation" were evaluated at the emergency room visit. The patient underwent the following laboratory tests and procedures: antithrombin iii: 69 %, notes: Low; computerised tomogram abdomen: revealed diffuse smv thrombosis with extension of, notes: revealed diffuse SMV thrombosis with extension of thrombus into the main and left hepatic portal veins; computerised tomogram pelvis: revealed diffuse smv thrombosis with extension of, notes: revealed diffuse SMV thrombosis with extension of thrombus into the main and left hepatic portal veins; physical examination: his abdomen was mildly distended but soft and non-, notes: tender with hypoactive bowel sounds; Russell's viper venom time: prolonged, notes: not corrected by phospholipid reagent; sars-cov-2 antibody test: 69, notes: AU/mL, which confirmed the presence of circulating IgG antibodies specific for SARS-CoV-2 at high levels; sars-cov-2 test: sars-cov-2 rna was not detected. Additional information: Further history revealed that he received both doses of the Pfizer- BioNTech (BNT162b2) mRNA COVID-19 vaccine, with the second dose administered 75 days prior to admission. There was no clear intra-abdominal inflammatory process, no sign of infection or malignancy, and no history of inherited thrombophilia. Patient was started on therapeutic enoxaparin subcutaneously. It was unclear if this patient's low ATIII levels were in the setting of acute thrombosis, or if they were low prior to thrombus formation and secondary to circulating Covid-19 antibodies. There have been a few case reports of individuals with vaccine-induced immune-thrombotic thrombocytopenia (ITTP), deep vein thrombosis (DVT), and acquired hemophilia. It is important to bring awareness to uncommon adverse events that may be linked to COVID-19 mRNA vaccine administration so that providers and patients can be aware of the possibility of these events and not delay diagnosis and treatment. Therapeutic measures were taken as a result of mesenteric vein thrombosis, portal vein thrombosis.  The lot number for bnt162b2 was not provided and will be requested during follow up.; Sender's Comments: Based on the information provided in the narrative, a causal association between the suspect drug and the events cannot be completely excluded. The impact of this report on the benefit/risk profile of the Pfizer product 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.