This 66-year-old, female subject was participating in a Study and experienced the adverse events of special interest (AESI) injection site soreness left (LT) arm, nausea, and probable myocarditis. The subject's medical history, as provided by the investigator, included right torn ligament, left eye cataract, post-menopausal, edema bilateral legs, anxiety, right eye cataract, hypertension, hypercholesterolemia, gastroesophageal reflux disease (GERD), epilepsy, sensory neuropathy in upper and lower extremities, back pain, and chronic bilateral leg pain. Concomitant medications included cholecalciferol, tramadol, cyanocobalamin, ascorbic acid/tocopheryl acetate/Xantofyl/zeaxanthin/zinc, famotidine, hydrochlorothiazide, alprazolam, metoprolol, losartan, paracetamol, pneumococcal vaccine conj. 7v (crm197), elasomeran, levetiracetam, venlafaxine, atorvastatin, nortriptyline, acetylsalicylic acid, and a multivitamin. The subject was randomized to receive intramuscular Placebo (dosed on 12 Aug 2020 and 15 Sep 2020) and was unblinded on 07 Jan 2021. The subject consented to receive mRNA-1273 for SARS-CoV-2 vaccination after being unblinded and, prior to event onset, the subject received mRNA-1273 (Dose 3, Booster) SARS-CoV-2 vaccination on 30 Nov 2021, approximately 4 months 14 days before onset of the event. On 12 Apr 2022, the subject experienced injection site soreness left (LT) arm, nausea, and probable myocarditis. Treatment included Pepto Bismol tablets for nausea and Dramamine for nausea and probable myocarditis. The subject received all scheduled doses of study drug prior to the event; therefore, action taken with study drug in response to the events, injection site soreness LT arm and probable myocarditis, was not applicable. Study drug dosing was withdrawn in response to the event nausea. The events, injection site soreness left (LT) arm, nausea, and probable myocarditis, were reported as not resolved. The investigator assessed the events, injection site soreness left (LT) arm, nausea, and probable myocarditis, as related to study drug and not related to study procedure. Company Comment: This case concerns a 66-year-old, white, female subject with a medical history of right torn ligament, left eye cataract, post-menopausal, edema bilateral legs, anxiety, right eye cataract, hypertension, hypercholesterolemia, gastroesophageal reflux disease (GERD), epilepsy, sensory neuropathy in upper and lower extremities, back pain, and chronic bilateral leg pain, who experienced the non-serious adverse events of special interest (AESI) injection site soreness left (LT) arm, nausea, and probable myocarditis. The events occurred 1 year 3 months after the first dose of IP and 4 months, 14 days after third (booster) dose of IP. The events were reported as not resolved. The investigator assessed the events as related to IP. The sponsor assessed the events as not related to IP. Additional information is requested.; Reporter's Comments: Company Comment: This case concerns a 66-year-old, white, female subject with a medical history of right torn ligament, left eye cataract, post-menopausal, edema bilateral legs, anxiety, right eye cataract, hypertension, hypercholesterolemia, gastroesophageal reflux disease (GERD), epilepsy, sensory neuropathy in upper and lower extremities, back pain, and chronic bilateral leg pain, who experienced the non-serious adverse events of special interest (AESI) injection site soreness left (LT) arm, nausea, and probable myocarditis. The events occurred 1 year 3 months after the first dose of IP and 4 months, 14 days after third (booster) dose of IP. The events were reported as not resolved. The investigator assessed the events as related to IP. The sponsor assessed the events as not related to IP. Additional information is requested.