mimics heartburn; acid reflux symptoms; discombobulated; kind of nervous; spacy feeling/ felt foggy/haven't been feeling good at all; mild inflammation of the heart; heart palpitations; arm hurt; body aches; she has not been feeling well since she received the booster dose; headache; fatigue/really, really bad fatigue; This spontaneous case was reported by a consumer and describes the occurrence of CARDITIS (mild inflammation of the heart) in a 65-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 053E21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No medical history was reported.  Concomitant products included BUSPIRONE HYDROCHLORIDE (BUSPAR) and ROSUVASTATIN CALCIUM (CRESTOR) for an unknown indication.    On 30-Oct-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 30-Oct-2021, the patient experienced PAIN IN EXTREMITY (arm hurt), PAIN (body aches), HEADACHE (headache) and FATIGUE (fatigue/really, really bad fatigue). 30-Oct-2021, the patient experienced MALAISE (she has not been feeling well since she received the booster dose). On 01-Nov-2021, the patient experienced CARDITIS (mild inflammation of the heart) (seriousness criterion medically significant), DYSPEPSIA (mimics heartburn), CONFUSIONAL STATE (discombobulated), PALPITATIONS (heart palpitations), NERVOUSNESS (kind of nervous) and FEELING ABNORMAL (spacy feeling/ felt foggy/haven't been feeling good at all). 01-Nov-2021, the patient experienced GASTROOESOPHAGEAL REFLUX DISEASE (acid reflux symptoms). The patient was treated with IBUPROFEN (MOTRIN [IBUPROFEN]) for Inflammation, at an unspecified dose and frequency and PARACETAMOL (TYLENOL [PARACETAMOL]) for Adverse event, at an unspecified dose and frequency. On 02-Nov-2021, PAIN IN EXTREMITY (arm hurt), HEADACHE (headache) and FATIGUE (fatigue/really, really bad fatigue) had resolved. At the time of the report, CARDITIS (mild inflammation of the heart), DYSPEPSIA (mimics heartburn), GASTROOESOPHAGEAL REFLUX DISEASE (acid reflux symptoms), CONFUSIONAL STATE (discombobulated), PALPITATIONS (heart palpitations), PAIN (body aches) and MALAISE (she has not been feeling well since she received the booster dose) had resolved and NERVOUSNESS (kind of nervous) and FEELING ABNORMAL (spacy feeling/ felt foggy/haven't been feeling good at all) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In November 2021, Electrocardiogram: normal (normal) EKG of her heart showed normal.         Dose 1 taken on 25-MAR-2021-Intramuscular-Left arm-044A2ZA. Dose 2 taken on 22-APR-2021-Left arm-007B21A. She did really well and did not experienced any side effects after first and second dose.; Sender's Comments: This case concerns a 66 year old female with no reported medical history , who experienced Serious, unexpected event of Palpitations and expected event of Cardiits ,  which occurred on the 3rd day after vaccination with the 3rd dose (booster dose) of mRNA-1273 vaccine (Moderna Covid 19 Vaccine ) . The re-challenge for this case is not applicable since no additional doses will be administered and the outcome of the events is unknown. The benefit-risk relationship of mRNA-1273 vaccine (Moderna Covid 19 Vaccine ) is not affected by this report.