Chronic heart failure; face was blistering; developed alpha gal allergy; This spontaneous case was reported by a patient and describes the occurrence of CARDIAC FAILURE CHRONIC (Chronic heart failure) and BLISTER (face was blistering) in a 76-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 038A21A and 014M20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product HEPARIN for an unknown indication.    Concurrent medical conditions included Chronic heart failure (a condition that he has had for many years prior to receiving any Moderna COVID-19 shots.).   On 20-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 26-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In 2021, the patient started HEPARIN (Intravenous) at an unspecified dose. In 2021, the patient experienced BLISTER (face was blistering) (seriousness criterion hospitalization prolonged) and FOOD ALLERGY (developed alpha gal allergy). On an unknown date, the patient experienced CARDIAC FAILURE CHRONIC (Chronic heart failure) (seriousness criteria hospitalization and medically significant). The patient was hospitalized on sometime in October 2021 due to CARDIAC FAILURE CHRONIC. At the time of the report, CARDIAC FAILURE CHRONIC (Chronic heart failure), BLISTER (face was blistering) and FOOD ALLERGY (developed alpha gal allergy) outcome was unknown.            No concomitant medications were reported. Patient was hospitalized in OCT-2021 due to chronic heart failure. He received IV heparin while at the hospital which caused an allergic reaction where his face started blistering. The doctors at the hospital could not figure out why he was reacting. He finally saw an allergist who diagnosed his allergy as Alpha gal allergy which means that he was allergic to red meat, dairy and basically mammal products that was caused by a lone star tick bite. He says that it was nothing to do with the Moderna COVID-19 vaccine as he has received 2 more doses (he has had 4 Moderna COVID-19 vaccine shots so far) after that and has not reacted to it. Moderna COVID-19 vaccines received prior to developing Alpha Gal allergy. No treatment medications were reported.  Company comment: This is a spontaneous case concerning a 76 years male patient, with Concurrent medical conditions included Chronic heart failure, who experienced the unexpected serious events of Cardiac failure chronic (hospitalization, medically significant), blister (hospitalization), which occurred unspecified days after second dose of mRNA-1273 vaccine. Additionally non serious event food allergy is also reported. Patient was hospitalized due to chronic heart failure, Patient received IV heparin when patient was in hospital, which caused allergic reaction, where patient face started blistering. Patient consulted allergist diagnosed Alpha gal allergy that was caused by lone star tick bite. At the time of reporting outcome of the events is unknown. Elderly age and concurrent medical conditions confounding for the event Cardiac failure chronic. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 76 years male patient, with Concurrent medical conditions included Chronic heart failure, who experienced the unexpected serious events of Cardiac failure chronic (hospitalization, medically significant), blister (hospitalization), which occurred unspecified days after second dose of mRNA-1273 vaccine. Additionally non serious event food allergy is also reported. Patient was hospitalized due to chronic heart failure, Patient received IV heparin when patient was in hospital, which caused allergic reaction, where patient face started blistering. Patient consulted allergist diagnosed Alpha gal allergy that was caused by lone star tick bite. At the time of reporting outcome of the events is unknown. Elderly age and concurrent medical conditions confounding for the event Cardiac failure chronic. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.