MYOCARDIAL INFARCTION; This approximately 68-year-old, male subject was participating in "A Phase 3, Randomized, Stratified, Observer-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1273 SARS-CoV-2 Vaccine in Adults Aged 18 Years and Older (mRNA-1273-P301)" and experienced serious adverse event of special interest (AESI) of myocardial infarction.  The subject's medical history, as provided by the investigator, included benign prostatic hyperplasia, myocardial infarction, hyperlipidemia, hypertension, coronary artery disease, kidney stones, lumbar spine bulging disc, left shoulder rotator tear, benign pituitary gland tumor, arthritis of right knee, and urinary frequency of unknown origin. Concomitant medications reported included acetylsalicylic acid, docusate sodium, paracetamol and tamsulosin.   The subject previously experienced serious adverse events of chest pressure - respiratory/shortness of breath - cardiac related from premature ventricular contractions (PVCs) (MOD-2021-001710), appendicitis and streptococcal anginosus blood stream infection (MOD-2021-011705) while participating in the study.  Prior to event onset, the subject received intramuscular mRNA-1273 (Dose 3) for SARS-CoV-2 vaccination on 14 Oct 2021, approximately 1 year 4 days before onset of the event. Additionally, the subject received Moderna COVID-19 Vaccine, bivalent (original and omicron BA.4/BA.5)(non-study booster) vaccine on 07 Oct 2022.  On 17 Oct 2022, the subject experienced myocardial infarction. The subject was hospitalized and underwent coronary artery stent placement for the event. He was admitted to the intensive care unit (ICU) for 5 days.  On 21 Oct 2022, the subject was discharged from the hospital.   The subject received all scheduled doses of study drug prior to the event; therefore, action taken with study drug in response to the event was not applicable.  The event, myocardial infarction, was reported as resolved on 17 Oct 2022.  The investigator assessed the event, myocardial infarction, as not related to study drug, not related to study procedure, and related to mRNA-1273 (non-study booster).   Follow-up received on 30 Nov 2022 and 01 Dec 2022 included confirmation of non-study booster vaccine information and intensive care admission details.  Company Comment: This 68-year-old, male subject, with the medical history, of benign prostatic hyperplasia, myocardial infarction, hyperlipidemia, hypertension, coronary artery disease, kidney stones, lumbar spine bulging disc, left shoulder rotator tear, benign pituitary gland tumor, arthritis of right knee, and urinary frequency of unknown origin, who experienced the unexpected serious adverse event of special interest (AESI) myocardial infarction. The event occurred 2 years 18 days after the subject received the first dose of mRNA-1273 and 1 year 4 days after the third (booster) dose of mRNA-1273. The participant also received a non-study Moderna booster 10 days before the onset of the event. The event was reported as resolved. The investigator assessed the event as not related to study drug and study procedure and related to the non-study booster. The sponsor considers the event as not related to the study drug and not related to the non-study booster based on subject medical history of myocardial infarction, hyperlipidemia, hypertension and coronary artery disease.