Transposition of the great arteries (LTGA)/ Baby born with LTGA; Mild and moderate/Tricuspid regurgitation; foetal exposure during pregnancy; This case was initially received via an unknown source (no reference has been entered for a health authority or license partner) on 10-Nov-2021. The most recent information was received on 23-Dec-2021 and was forwarded to Moderna on 23-Dec-2021.    This case was initially received via an unknown source (no reference has been entered for a health authority or license partner) on 10-Nov-2021. The most recent information was received on 23-Dec-2021 and was forwarded to Moderna on 23-Dec-2021.    This spontaneous case was reported by a consumer and describes the occurrence of TRANSPOSITION OF THE GREAT VESSELS (Transposition of the great arteries (LTGA)/ Baby born with LTGA) and TRICUSPID VALVE INCOMPETENCE (Mild and moderate/Tricuspid regurgitation) in a 3-month-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 025J20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    MEDICAL HISTORY (Parent): On 27-Jul-2021 lab test was done Fetal echo with result: L-TOA (abnormal) On an unknown date, Fetal non-stress test was done with result: normal (multiple throughout the pregnancy to monitor movement) and also test ultrasound fetoe test was done with result: biophysical profile to monitor growth normal findings baby was small  On an unknown date in 2021, pregnancy test was done with result: positive On 19-Jul-2021, abdominal ultrasound test was done with result: abnormal (congenitally corrected L-transposition of the greater vessel) On an unknown date, the mother started taking Prenatal vitamins orally. The parent received the Moderna vaccine during the time that the heart was forming. It was also reported that other children were being tested on 10-Dec-2021, and were confirmed to have no heart defects. Her husband and as well the mother got tested for any genetic markers and waiting for the results which might take about 8 weeks. That type of heart anomaly was not one to be associated with genetic markers.  The mother's past medical history included Maternal exposure during pregnancy on 23-Dec-2020. Previously administered products included for Product used for unknown indication: ASA (Dose: 85 mg and Route: PO (oral)) from 04-Aug-2021 to 20-Aug-2021. Concurrent medical conditions included Drug allergy.    MEDICAL HISTORY (Patient): The patient's past medical history included Maternal exposure during pregnancy (in the time frame in which the heart was forming in utero.) on 23-Dec-2020.    On 23-Dec-2020, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Transplacental) 1 dosage form. On 23-Dec-2020, the patient experienced FOETAL EXPOSURE DURING PREGNANCY (foetal exposure during pregnancy). On 02-Jun-2021, the patient experienced TRANSPOSITION OF THE GREAT VESSELS (Transposition of the great arteries (LTGA)/ Baby born with LTGA) (seriousness criteria death, medically significant and congenital anomaly) and TRICUSPID VALVE INCOMPETENCE (Mild and moderate/Tricuspid regurgitation) (seriousness criteria medically significant and congenital anomaly). The patient died on 24-Nov-2021. The reported cause of death was transposition of the great arteries (ltga)/ baby born with ltga. An autopsy was not performed. At the time of death, TRICUSPID VALVE INCOMPETENCE (Mild and moderate/Tricuspid regurgitation) had not resolved and FOETAL EXPOSURE DURING PREGNANCY (foetal exposure during pregnancy) had resolved.        mRNA-1273 (Moderna COVID-19 Vaccine) (Transplacental) was withdrawn on an unknown date.       No concomitant and treatment medication were provided.  Company comment: This spontaneous case concerns a 3-month-old, male patient with Fetal Exposure During Pregnancy (approximately at 2 weeks of gestational age, transplacental exposure) to the first dose of mRNA-1273 vaccine, who was born with transposition of the great vessels (Transposition of the great arteries (LTGA)) and tricuspid valve incompetence (mild and moderate/tricuspid regurgitation) and died due to transposition of the great vessels at 3 months of age. An autopsy was not performed. During pregnancy, an anatomical scan had confirmed a diagnosis of congenitally L-transposition of the greater artery. The child was born by vaginal delivery and was full term with the mentioned congenital anomalies. The mother had two older children with no congenital anomalies, the reporter informed that genetic testing showed no relationship to the baby's diagnosis to the parents and genetic tests and other evaluations were ongoing at the time of the follow-up report. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Case was assessed as serious due to important medical event, congenital anomaly and death.  This spontaneous case concerns a 3-month-old, male patient with Fetal Exposure During Pregnancy (approximately at 2 weeks of gestational age, transplacental exposure) to the first dose of mRNA-1273 vaccine, who was born with transposition of the great vessels (Transposition of the great arteries (LTGA)) and tricuspid valve incompetence (mild and moderate/tricuspid regurgitation) and died due to transposition of the great vessels at 3 months of age. Autopsy reported  Transposition of the great arteries (LTGA)/ Baby born with LTGA as the cause of death. During pregnancy, an anatomical scan had confirmed a diagnosis of congenitally L-transposition of the greater artery. The child was born by vaginal delivery and was full term with the mentioned congenital anomalies. The mother had t   This case was linked to MOD-2021-223997 (Parent-Child Link).   See case MOD-2021-223997 for details regarding the child case.  Most recent FOLLOW-UP information incorporated above includes: On 23-Dec-2021: Significant follow up received on 23-Dec-2021: Patient's Death date, autopsy details, Suspect batch number, onset date and end date for the event (Anomaly heart) were added and reporter causality of all events except foetal exposure during pregnancy updated (previously not provided).; Sender's Comments: This spontaneous case concerns a 3-month-old, male patient with Fetal Exposure During Pregnancy (approximately at 2 weeks of gestational age, transplacental exposure) to the first dose of mRNA-1273 vaccine, who was born with transposition of the great vessels (Transposition of the great arteries (LTGA)) and tricuspid valve incompetence (mild and moderate/tricuspid regurgitation) and died due to transposition of the great vessels at 3 months of age. Autopsy reported  Transposition of the great arteries (LTGA)/ Baby born with LTGA as the cause of death. During pregnancy, an anatomical scan had confirmed a diagnosis of congenitally L-transposition of the greater artery. The child was born by vaginal delivery and was full term with the mentioned congenital anomalies. The mother had two older children with no congenital anomalies, the reporter informed that genetic testing showed no relationship to the baby's diagnosis to the parents and genetic tests and other evaluations were ongoing at the time of the follow-up report. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Case was assessed as serious due to important medical event, congenital anomaly and death. For the events transposition of great arteries and tricuspid valve incompetence, the reporters assessment is that it is related to the vaccine.; Reported Cause(s) of Death: Transposition of the great arteries (LTGA)/ Baby born with LTGA