heart failure; aortic valve insufficiency; This spontaneous case was reported by a patient and describes the occurrence of CARDIAC FAILURE (heart failure) and AORTIC VALVE INCOMPETENCE (aortic valve insufficiency) in a 78-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 0391721A, 023M20A and 028L20A) for COVID-19 prophylaxis.     The patient's past medical history included COVID-19 in January 2023 and Aortic valve replacement (Transvascular aortic valve replacement,) in 2019. Concurrent medical conditions included Pericarditis since February 2023, Blood pressure high, Eosinophilic esophagitis and Aortic stenosis. Concomitant products included EVOLOCUMAB (REPATHA) for High cholesterol, ACETYLSALICYLIC ACID (BABY ASPIRIN), COLCHICINE and PREDNISONE for an unknown indication.   On 18-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 16-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 22-Oct-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced CARDIAC FAILURE (heart failure) (seriousness criterion medically significant) and AORTIC VALVE INCOMPETENCE (aortic valve insufficiency) (seriousness criterion medically significant). At the time of the report, CARDIAC FAILURE (heart failure) and AORTIC VALVE INCOMPETENCE (aortic valve insufficiency) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Other medical history information included high cholesterol which treated with Repatha (statins).  Patient reported back in 2019 patient had severe aortic stenosis, with his native/natural valve. Patient needed a transvascular aortic valve replacement, which was performed on 2019. The new valve worked very well. Patient stated that he was not symptomatic, but the natural valve couldn´t stay, patient was told he could die if it was not replaced. Then the new valve started leaking 2 years later. Patient had moderate aortic valve insufficiency. Patient was told again he should replace it because it could get worse and could die.  No treatment information was provided. Company comment- This spontaneous case concerns a 78-year-old male patient, with medical history of high blood pressure and severe aortic stenosis which required a trans vascular aortic valve replacement, who experienced the unexpected serious (medically significant) events of cardiac failure (AESI) and aortic valve incompetence. Three doses of mRNA-1273 vaccine were administered in a n appropriate schedule of vaccination. Exact onset date of the events was not provided; hence, latency cannot be assessed.  It was reported patient had, 2 years before vaccination, a severe aortic stenosis, with his native/natural valve, which required a trans vascular aortic valve replacement. The new valve worked very well but after 2 years the new valve started leaking. He developed a moderate aortic valve insufficiency. He was told again he should replace it because it could get worse. He went through different stages of aortic insufficiency and heart failure. Finally, the patient had an open-heart surgery. Medical history of severe aortic stenosis and high blood pressure remain as confounders. The benefit risk relationship of mRNA-1273 is not affected by this report.   This case was linked to MOD-2023-724010 (Patient Link).