graves disease; Thyroxine increased; Tri-iodothyroxine; Blood Thyroid Stimulating Hormone; Thyroid Stimulating Immunoglobulin; thyroiditis; Severe headache; Felt dead tired, severe fatigue; nausea; Body aches; temperature was 100.2; palpitations; This spontaneous case was reported by a physician and describes the occurrence of BASEDOW'S DISEASE (graves disease), THYROXINE INCREASED (Thyroxine increased), TRI-IODOTHYRONINE INCREASED (Tri-iodothyroxine), BLOOD THYROID STIMULATING HORMONE DECREASED (Blood Thyroid Stimulating Hormone) and THYROID STIMULATING IMMUNOGLOBULIN INCREASED (Thyroid Stimulating Immunoglobulin) in a 51-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 007M20A and 025L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Sulfonamide allergy, Drug allergy (lansoprazole), Asthma since 2012, Breast cancer since 2012 and Drug allergy (tobramycin). Concomitant products included TAMOXIFEN from 02-Mar-2015 to an unknown date for Breast cancer, DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL A) for Insomnia, ONDANSETRON (ZOFRAN [ONDANSETRON]) from 2012 to an unknown date for Nausea, ALBUTEROL [SALBUTAMOL], CALCIUM CARBONATE, COLECALCIFEROL (VITAMIN D 2000), ZINC from December 2020 to an unknown date, ASCORBIC ACID (VIT C) and CURCUMA LONGA (TURMERIC [CURCUMA LONGA]) from December 2020 to an unknown date for an unknown indication.   On 07-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 04-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 05-Feb-2021, the patient experienced PALPITATIONS (palpitations), NAUSEA (nausea), MYALGIA (Body aches) and PYREXIA (temperature was 100.2). On 11-Mar-2021, the patient experienced HEADACHE (Severe headache) and FATIGUE (Felt dead tired, severe fatigue). On an unknown date, the patient experienced BASEDOW'S DISEASE (graves disease), THYROXINE INCREASED (Thyroxine increased), TRI-IODOTHYRONINE INCREASED (Tri-iodothyroxine), BLOOD THYROID STIMULATING HORMONE DECREASED (Blood Thyroid Stimulating Hormone), THYROID STIMULATING IMMUNOGLOBULIN INCREASED (Thyroid Stimulating Immunoglobulin) and THYROIDITIS (thyroiditis). The patient was treated with PARACETAMOL (TYLENOL) at an unspecified dose and frequency; DIPHENHYDRAMINE, PARACETAMOL, PHENYLPROPANOLAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE;PARACETAMOL;PHENYLPROPANOLAMINE HYDROCHLORIDE]) at an unspecified dose and frequency and IBUPROFEN at an unspecified dose and frequency. At the time of the report, BASEDOW'S DISEASE (graves disease), THYROXINE INCREASED (Thyroxine increased), TRI-IODOTHYRONINE INCREASED (Tri-iodothyroxine), BLOOD THYROID STIMULATING HORMONE DECREASED (Blood Thyroid Stimulating Hormone), THYROID STIMULATING IMMUNOGLOBULIN INCREASED (Thyroid Stimulating Immunoglobulin), THYROIDITIS (thyroiditis), PALPITATIONS (palpitations), NAUSEA (nausea), MYALGIA (Body aches) and PYREXIA (temperature was 100.2) outcome was unknown and HEADACHE (Severe headache) and FATIGUE (Felt dead tired, severe fatigue) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 29-Apr-2016, Blood cholesterol: 217 (High) 217 mg/dl. On 29-Apr-2016, Full blood count: unknown (Inconclusive) unknown. On 29-Apr-2016, Metabolic function test: unknown (Inconclusive) unknown. In 2016, Anti-thyroid antibody: normal (normal) normal. On 07-Jul-2020, Blood cholesterol: 249 (High) 249 mg/dl. On 07-Jul-2020, Low density lipoprotein: 132 (High) 132 mg/dl. On 20-Jul-2020, Blood thyroid stimulating hormone: normal (normal) normal. On 20-Jul-2020, Thyroxine free: normal (normal) normal. On 20-Jul-2020, Vitamin D: 28 (Low) 28 ng/ML. On 11-Mar-2021, Blood chloride: 97 (Low) 97. On 11-Mar-2021, Blood cholesterol: 238 (High) 238 mg/dl. On 11-Mar-2021, Blood thyroid stimulating hormone: 0.08 (Low) 0.08 mIU/L. On 11-Mar-2021, High density lipoprotein: 146 (High) 146 mg/dl. On 11-Mar-2021, Low density lipoprotein: 129 (High) 129 mg/dl. On 11-Mar-2021, SARS-CoV-2 antibody test positive: positive (Inconclusive) Positive. On 11-Mar-2021, Thyroxine free: normal (normal) normal. On 31-Mar-2021, Anti-thyroid antibody: 24 (High) 24 IU/mL. On 31-Mar-2021, Anti-thyroid antibody positive: 2.61 (High) IU/L. On 31-Mar-2021, Blood thyroid stimulating hormone: 0.03 (Low) 0.03 mIU/L. On 31-Mar-2021, Thyroxine free: normal (normal) normal. On 23-Apr-2021, Anti-thyroid antibody: 27 (High) 27 IU/mL. On 23-Apr-2021, Blood thyroid stimulating hormone: less than 0.01 (Low) 0.01 mIU/L. On 23-Apr-2021, Thyroid stimulating immunoglobulin: 4.5 (High) 4.5 TSI index;  Standard Range <1.3 TSI index. On 23-Apr-2021, Thyroxine free: normal (normal) normal. On 03-May-2021, Blood thyroid stimulating hormone: 0.01 (Low) 0.01 mIU/L. On 03-May-2021, Thyroid stimulating immunoglobulin: 235 (High) 235 H. On 03-May-2021, Thyroxine free: 2.5 (High) 2.5 ng/dL. On 03-May-2021, Tri-iodothyronine: 192 (High) 192 ng/dL. On 03-May-2021, Vitamin B12: 1596 (High) 1596 pg/ml. On 14-May-2021, Anti-thyroid antibody: 24 (High) 24 IU/mL. On 14-May-2021, Thyroid stimulating immunoglobulin: 343 (High) 343 H. On 14-May-2021, Tri-iodothyronine: 186 (High) 186 ng/dL.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered BASEDOW'S DISEASE (graves disease) to be possibly related. No further causality assessments were provided for THYROXINE INCREASED (Thyroxine increased), TRI-IODOTHYRONINE INCREASED (Tri-iodothyroxine), BLOOD THYROID STIMULATING HORMONE DECREASED (Blood Thyroid Stimulating Hormone), THYROID STIMULATING IMMUNOGLOBULIN INCREASED (Thyroid Stimulating Immunoglobulin), THYROIDITIS (thyroiditis), PALPITATIONS (palpitations), HEADACHE (Severe headache), NAUSEA (nausea), MYALGIA (Body aches), PYREXIA (temperature was 100.2) and FATIGUE (Felt dead tired, severe fatigue).    Concomitant medication included Olly Happy Gummies (saffron 30mg,2000IU vitamin D) started Feb 2021, Vitafurion Immune C gummies(Vit C, Vit D, zinc) started May 2021.  Treatment drug Zofran unknown dosage, unknown frequency listed as a concomitant drug.  Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.   Most recent FOLLOW-UP information incorporated above includes: On 09-Jun-2021: Follow up received on 09-JUN-2021 included patient's details, medical history, concomitant medication, new event. On 09-Jun-2021: Follow up received on 09-JUN-2021 included non significant follow up On 09-Jun-2021: No specific follow-up information recorded.; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.