I've been largely unable to perform basic functions, including cooking, walking around my house, exercising, or working; Difficulty breathing; Chest pain; Difficulty eating; I lay in bed all day/when standing or walking a few feet, had to stay in bed for significant portions of the day; Body Aches; Nausea; Palpitations; Inability to sit up, work/when standing or walking a few feet, had to stay in bed for significant portions of the day; Loss of appetite; Shakiness/shivers; Brain fog; I started to feel fatigue/fatigue; Extreme fatigue; Veryhighfever; Chills/shivers; I tried to stand up to brush my teeth I felt dizzy/I lay in bed all day; Extremely sick; tachycardia; posterior orthostatic tachycardia syndrome; This spontaneous case was reported by a consumer and describes the occurrence of TACHYCARDIA (tachycardia), POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (posterior orthostatic tachycardia syndrome), CHEST PAIN (Chest pain), LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (I've been largely unable to perform basic functions, including cooking, walking around my house, exercising, or working) and PALPITATIONS (Palpitations) in a 27-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 012H21B) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Previously administered products included for Product used for unknown indication: Pfizer vaccine on 05-Apr-2021 and Pfizer vaccine on 26-Apr-2021. Past adverse reactions to the above products included No adverse event with Pfizer vaccine and Pfizer vaccine. Concurrent medical conditions included Birth control. Concomitant products included LEVONORGESTREL (MIRENA) from 11-Jan-2018 to an unknown date for Birth control.    On 27-Nov-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .25 milliliter. On 27-Nov-2021, the patient experienced TACHYCARDIA (tachycardia), ILLNESS (Extremely sick), DIZZINESS (I tried to stand up to brush my teeth I felt dizzy/I lay in bed all day), PYREXIA (Veryhighfever), CHILLS (Chills/shivers) and FATIGUE (Extreme fatigue). 27-Nov-2021, the patient experienced POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (posterior orthostatic tachycardia syndrome). On 07-Dec-2021, the patient experienced FATIGUE (I started to feel fatigue/fatigue). On 10-Dec-2021, the patient experienced PALPITATIONS (Palpitations), IMPAIRED WORK ABILITY (Inability to sit up, work/when standing or walking a few feet, had to stay in bed for significant portions of the day), DECREASED APPETITE (Loss of appetite), TREMOR (Shakiness/shivers), FEELING ABNORMAL (Brain fog), DYSPHAGIA (Difficulty eating), BEDRIDDEN (I lay in bed all day/when standing or walking a few feet, had to stay in bed for significant portions of the day), MYALGIA (Body Aches) and NAUSEA (Nausea). On 15-Dec-2021, the patient experienced CHEST PAIN (Chest pain) and DYSPNOEA (Difficulty breathing). On an unknown date, the patient experienced LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (I've been largely unable to perform basic functions, including cooking, walking around my house, exercising, or working). The patient was treated with PROPRANOLOL for Adverse event, at a dose of bid. On 28-Nov-2021, ILLNESS (Extremely sick), DIZZINESS (I tried to stand up to brush my teeth I felt dizzy/I lay in bed all day), PYREXIA (Veryhighfever), CHILLS (Chills/shivers) and FATIGUE (Extreme fatigue) had resolved. At the time of the report, TACHYCARDIA (tachycardia), POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (posterior orthostatic tachycardia syndrome), PALPITATIONS (Palpitations), FEELING ABNORMAL (Brain fog) and FATIGUE (I started to feel fatigue/fatigue) was resolving, CHEST PAIN (Chest pain), LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (I've been largely unable to perform basic functions, including cooking, walking around my house, exercising, or working), DYSPNOEA (Difficulty breathing) and DYSPHAGIA (Difficulty eating) outcome was unknown, IMPAIRED WORK ABILITY (Inability to sit up, work/when standing or walking a few feet, had to stay in bed for significant portions of the day) and BEDRIDDEN (I lay in bed all day/when standing or walking a few feet, had to stay in bed for significant portions of the day) had not resolved and DECREASED APPETITE (Loss of appetite), TREMOR (Shakiness/shivers), MYALGIA (Body Aches) and NAUSEA (Nausea) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 27-Nov-2021, Heart rate: 90-120 (High) resting heart rate was 90-120 and 200 (High) heart rate got up to 200. On 03-Dec-2021, Electrocardiogram: results not reported (Inconclusive) Results not reported EKGs and Holter Monitor showed tachycardia. On 10-Dec-2021, Blood thyroid stimulating hormone: results not reported (Inconclusive) Results not reported. On 10-Dec-2021, Full blood count: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Alanine aminotransferase: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Aspartate aminotransferase: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Blood alkaline phosphatase: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Blood bilirubin: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Blood calcium: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Blood lactic acid: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Blood magnesium: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Blood phosphorus: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Brain natriuretic peptide: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, C-reactive protein: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Chest X-ray: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Differential white blood cell count: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Electrocardiogram: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Fibrin D dimer: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Full blood count: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Lipase: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Red blood cell sedimentation rate: results not reported (Inconclusive) Results not reported. On 13-Dec-2021, Troponin I: results not reported (Inconclusive) Results not reported. On 15-Dec-2021, Blood calcium: results not reported (Inconclusive) Results not reported. On 15-Dec-2021, Blood magnesium: results not reported (Inconclusive) Results not reported. On 15-Dec-2021, Blood phosphorus: results not reported (Inconclusive) Results not reported. On 15-Dec-2021, Differential white blood cell count: results not reported (Inconclusive) Results not reported. On 15-Dec-2021, Electrocardiogram: results not reported (Inconclusive) Results not reported. EKG done twice on 15-DEC-2021.. On 15-Dec-2021, Full blood count: results not reported (Inconclusive) Results not reported. On 15-Dec-2021, SARS-CoV-2 test: results not reported (Inconclusive) Results not reported. On 16-Dec-2021, Electrocardiogram: results not reported (Inconclusive) Results not reported. On 16-Dec-2021, Electrocardiogram ambulatory: results not reported (Inconclusive) Results not reported. 24hrs. On 17-Dec-2021, Blood bicarbonate: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood calcium: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood chloride: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood glucose: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood magnesium: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood phosphorus: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood potassium: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood sodium: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Blood urea: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Brain natriuretic peptide: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, C-reactive protein: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Electrocardiogram: results not reported (Inconclusive) Results not reported. On 17-Dec-2021, Troponin I: results not reported (Inconclusive) Results not reported. On 23-Dec-2021, Echocardiogram: results not reported (Inconclusive) Results not reported. On an unknown date, Blood test: results not reported (Inconclusive) Results not reported. On an unknown date, Cardiac function test: results not reported (Inconclusive) Results not reported. On an unknown date, Chest X-ray: results not reported (Inconclusive) Results not reported. On an unknown date, Electrocardiogram: results not reported (Inconclusive) Results not reported. On an unknown date, Heart rate: 150-200 (High) For first few weeks heart rate was 150-200 and 120-140 (High) Heart rate now is 120-140 when she stands up.. On an unknown date, Myocardial necrosis marker: results not reported (Inconclusive) Results not reported.         Patient stated that she went to the ER twice  since receiving the Moderna booster vaccine but was not hospitalized.Before receiving the COVID booster, patient  exercised 5-7 times a week, worked 40 hours a week, and had no preexisting conditions, resting heart rates during sleep were typically 50-60, heart rates during the day typically 60-85, heart rates while going on a walk typically 100-110, heart rates with running/high intensity exercise typically 145-185. After receiving the booster, patient had been largely unable to perform basic functions, including cooking, walking around my house, exercising, or working.  From 28 Nov 2021 to 6 Dec 2021, the  heart rates were higher than normal but had no other symptoms and was able to do normal activities. On 10 Dec 2021, patient woke up feeling like been hit by a truck,  had very erratic and high heart rates (47-209).Patient stated that symptoms intermittently improved, but 70% of the time continued to feel extremely fatigued with very erratic and high heart rates and symptoms have moderately improved with high salt diet, high fluid intake, and rest.Patient was advised to increase salt intake to 4-5 grams. On 10-DEC-2021 patient was examined for non fasting lipid panel with results not reported. On 13-DEC-2021 and 15-DEC-2021 chemistry panel was done with results not reported. On 17-DEC-2021 creatinine and calculated glomerular was done with results not reported. On 22-DEC-2021 24 hour urine metanephrines and catecholamines was done sults not reported.  CC: This case concerns a 27-year-old female patient with no relevant medical history, who experienced the non-serious, unexpected AESI of Postural orthostatic tachycardia syndrome. The event occurred 10 hours after the booster dose of mRNA-1273 vaccine. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 03-Jan-2022: Significant follow up, Added patient demographics, laboratory tests and events and concomitant medication details, events onset date for the symptoms updated.; Sender's Comments: This case concerns a 27-year-old female patient with no relevant medical history, who experienced the non-serious, unexpected AESI of Postural orthostatic tachycardia syndrome. The event occurred 10 hours after the booster dose of mRNA-1273 vaccine. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.