hyperactive/hyperthyroid Heart fluttering/ Heart palpitation/heart beats all over the place randomly/ Anxiety; a lot of anxiety; still with pain on the injection site, left arm; Missed dose; This spontaneous case was reported by a consumer and describes the occurrence of HYPERTHYROIDISM (hyperactive/hyperthyroid Heart fluttering/ Heart palpitation/heart beats all over the place randomly/ Anxiety; a lot of anxiety) in a 40-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 045J21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Patient not had both Acute and Chronic illnesses at the time of vaccination.  Previously administered products included for Product used for unknown indication: FLU [INFLUENZA VACCINE] (7 YEARS AGO). Past adverse reactions to the above products included No adverse event with FLU [INFLUENZA VACCINE]. Concurrent medical conditions included Seafood allergy (CRABS) and Seafood allergy (LOBSTERS).    On 28-Dec-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced HYPERTHYROIDISM (hyperactive/hyperthyroid Heart fluttering/ Heart palpitation/heart beats all over the place randomly/ Anxiety; a lot of anxiety) (seriousness criterion medically significant), VACCINATION SITE PAIN (still with pain on the injection site, left arm) and PRODUCT DOSE OMISSION ISSUE (Missed dose). The patient was treated with METHIMAZOLE at a dose of UNK UNK, qd(once a day) and PROPRANOLOL at a dose of UNK UNK, qd(once a day). At the time of the report, HYPERTHYROIDISM (hyperactive/hyperthyroid Heart fluttering/ Heart palpitation/heart beats all over the place randomly/ Anxiety; a lot of anxiety) and VACCINATION SITE PAIN (still with pain on the injection site, left arm) had not resolved and PRODUCT DOSE OMISSION ISSUE (Missed dose) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Cardiac stress test: normal (normal) normal. On an unknown date, Echocardiogram: normal (normal) normal.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant medications was not provided by the reporter.  Patient not had had COVID + test or diagnosis. Patient not diagnosed with myocarditis or pericarditis. Patient not had any history of COVID-19 infection.  Company Comment:  This spontaneous case concerns a 40-year-old female patient with no relevant medical history, who experienced the unexpected serious (medically significant) adverse event of special interest Hyperthyroidism, that occurred on an unknown date after receiving the first dose of mRNA-1273 vaccine.  Patient presented to the emergency room with palpitations, anxiety, and heart flutters approximately 2 months after vaccination, and was diagnosed with Hyperthyroidism. It was reported that thyroid was very low for which Methimazole, and Propranolol were given as treatment.  Cardiac stress test and echocardiogram were both reported with normal results. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 40-year-old female patient with no relevant medical history, who experienced the unexpected serious (medically significant) adverse event of special interest Hyperthyroidism, that occurred on an unknown date after receiving the first dose of mRNA-1273 vaccine.  Patient presented to the emergency room with palpitations, anxiety, and heart flutters approximately 2 months after vaccination, and was diagnosed with Hyperthyroidism. It was reported that thyroid was very low for which Methimazole, and Propranolol were given as treatment.  Cardiac stress test and echocardiogram were both reported with normal results. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.