Congested heart failure; Bruising; Low palettes; Felt like he was going to pass out; Fatigue; Weakness; This spontaneous case was reported by a consumer and describes the occurrence of CARDIAC FAILURE CONGESTIVE (Congested heart failure), FATIGUE (Fatigue), ASTHENIA (Weakness), CONTUSION (Bruising), PRESYNCOPE (Felt like he was going to pass out) and PLATELET COUNT DECREASED (Low palettes) in a 55-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     The patient's past medical history included Colon cancer.   In April 2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In 2021, the patient experienced FATIGUE (Fatigue) (seriousness criterion hospitalization), ASTHENIA (Weakness) (seriousness criterion hospitalization) and PRESYNCOPE (Felt like he was going to pass out) (seriousness criterion hospitalization). On an unknown date, the patient experienced CARDIAC FAILURE CONGESTIVE (Congested heart failure) (seriousness criteria hospitalization and medically significant), CONTUSION (Bruising) (seriousness criterion hospitalization) and PLATELET COUNT DECREASED (Low palettes) (seriousness criterion hospitalization). The patient was hospitalized on sometime in August 2021 due to ASTHENIA, CARDIAC FAILURE CONGESTIVE, CONTUSION, FATIGUE, PLATELET COUNT DECREASED and PRESYNCOPE. At the time of the report, CARDIAC FAILURE CONGESTIVE (Congested heart failure), FATIGUE (Fatigue), ASTHENIA (Weakness), CONTUSION (Bruising), PRESYNCOPE (Felt like he was going to pass out) and PLATELET COUNT DECREASED (Low palettes) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood test: normal (normal) Normal. On an unknown date, Ejection fraction: 30% (abnormal) 30%. On an unknown date, Platelet count: low (Low) low.         Concomitant medications was not reported. Treatment history was not reported. The patient was in remission from colon cancer and he was well for over a year now. The patient was on his recovery from cancer. Since last few weeks, he was experiencing fatigue weakness and felt like he was going to pass out. He was admitted to hospital last week and discharged after 4 days. Till date he was not fully diagnosed yet. His symptoms were low platelets with bruising, ejection was at 30% (blood flow) which was told that it is a congested heart failure, very fatigued and weak. He was tested by hematologist for leukemia and results did not find anything and blood tests came back ok. They still did not have a diagnosis. His oncologist planned to consult with the heart doctor that he seen while in hospital and he had a follow up appointment with heart doctor in September 2021.  Based on the current available information and temporal association between the use of the product and the start date of events, a causal relationship cannot be excluded. However, patient's previous history of colon cancer can be a confounding factor. Further information is requested.; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of events, a causal relationship cannot be excluded. However, patient's previos history of colon cancer can be a confounding factor. Further information is requested.