Recurrent AvWD; Acquired hemophilia A; Admitted for Blood loss anemia; On day 7, she developed persistently melanotic stool; After dose 2, On day 4 she developed large ecchymoses covering most of her upper extremities; On day 15 she presented to the emergency department with presyncope; This case was reported in a literature article and describes the occurrence of ACQUIRED VON WILLEBRAND'S DISEASE (Recurrent AvWD), ACQUIRED HAEMOPHILIA (Acquired hemophilia A), BLOOD LOSS ANAEMIA (Admitted for Blood loss anemia) and MELAENA (On day 7, she developed persistently melanotic stool) in a 76-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.   LITERATURE REFERENCE:      The patient's past medical history included Ecchymoses (multiple episodes of large, upper extremity), Paraesophageal hiatal hernia and Nissen fundoplication (status post recent uncomplicated). Concurrent medical conditions included Asthma and Raynaud's phenomenon.   On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient experienced ACQUIRED VON WILLEBRAND'S DISEASE (Recurrent AvWD) (seriousness criteria hospitalization and medically significant), ACQUIRED HAEMOPHILIA (Acquired hemophilia A) (seriousness criteria hospitalization and medically significant), BLOOD LOSS ANAEMIA (Admitted for Blood loss anemia) (seriousness criteria hospitalization and medically significant), MELAENA (On day 7, she developed persistently melanotic stool) (seriousness criterion medically significant), ECCHYMOSIS (After dose 2, On day 4 she developed large ecchymoses covering most of her upper extremities) and PRESYNCOPE (On day 15 she presented to the emergency department with presyncope). The patient was hospitalized for 28 days due to ACQUIRED HAEMOPHILIA, ACQUIRED VON WILLEBRAND'S DISEASE and BLOOD LOSS ANAEMIA. The patient was treated with METHYLPREDNISOLONE for Adverse event, at a dose of 125 milligram every six hours; METHYLPREDNISOLONE for Adverse event, at a dose of 125 milligram twice a day; PREDNISONE for Adverse event, at a dose of 50 milligram twice a day and PREDNISONE for Adverse event, at a dose of 50 milligram once a day. At the time of the report, ACQUIRED VON WILLEBRAND'S DISEASE (Recurrent AvWD), ACQUIRED HAEMOPHILIA (Acquired hemophilia A), BLOOD LOSS ANAEMIA (Admitted for Blood loss anemia), MELAENA (On day 7, she developed persistently melanotic stool), ECCHYMOSIS (After dose 2, On day 4 she developed large ecchymoses covering most of her upper extremities) and PRESYNCOPE (On day 15 she presented to the emergency department with presyncope) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2021, Activated partial thromboplastin time: 122 Second (High) 122 s; mildly prolonged. In 2021, Anti factor VIII antibody test: high (High) High; uptrending and less than 3 (Inconclusive) less than 3 percent. In 2021, Coagulation time: prolonged (Inconclusive) abnormalities illustrates a durable immune response and highlights the utility of corticosteroids in eliminating an autoantibody inhibitor. In 2021, Electrophoresis protein: monoclonal protein was not detected (Inconclusive) Monoclonal protein was not detected. In 2021, International normalised ratio: 1.5 (Inconclusive) 1.5. In 2021, Platelet aggregation test: abnormal (abnormal) abnormal ristocetin. In 2021, SARS-CoV-2 test: negative (Negative) negative. In 2021, Von Willebrand's factor activity test: abnormal (abnormal) showed a normal pattern and distribution of bands, consistent with a quantitative vWF deficiency, high (High) High; uptrending, 5 (Inconclusive) 5 percent and less than 3 percent (Inconclusive) less than 3 percent.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered ACQUIRED VON WILLEBRAND'S DISEASE (Recurrent AvWD), ACQUIRED HAEMOPHILIA (Acquired hemophilia A), BLOOD LOSS ANAEMIA (Admitted for Blood loss anemia), MELAENA (On day 7, she developed persistently melanotic stool), ECCHYMOSIS (After dose 2, On day 4 she developed large ecchymoses covering most of her upper extremities) and PRESYNCOPE (On day 15 she presented to the emergency department with presyncope) to be possibly related.    Concomitant medications were not provided by the reporter.  The patient was diagnosed with recurrent Acquired Von Willebrand's disease (AvWD) and acquired hemophilia A, presumed to be due to an antibody directed against the Factor (FVIII)/von Willebrand factor (vWF) complex.  After dose 2 on days 17 to 19, vWF/FVIII replacement therapy was provided with Humate-P 2290 International unit (U) every 12 hours x 4 doses.Reduction of factor inhibitors was achieved using IV immunoglobulin (IVIg) and corticosteroids as follows: IVIg1g/kg on days 18 and19. On an unknown date lab test included were A factor VIII inhibitor was detected and quantified as 11.2 Bethesda units (BUs) also on days 19 and 26, levels were 1.6 BUs and 0.5 BUs respectively. It was thought to had triggered a flare of an underlying autoimmune- or complement-mediated hematologic condition.The rapid normalization of FVIII and vWF activity after administration of Intravenous immunoglobulin (IVIg) was suggestive of an IgG antibody-mediated process against endogenous and exogenous FVIII/vWF complex.   This case was linked to MOD-2021-263889, MOD-2021-263965 (Patient Link).; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded. A literature review case.