Flank pain that wrapped around my back & the front of my stomach; chest tightness; sinus tachycardia; shortness of breath;  response; Pericardial effusion; They found 100 tiny kidney stones; Gallbladder pain; I had kidney pain.; Gums were inflamed; My whole body was inflamed; inflammation in my  stomach; inflammation in my esophagus.; I'm having more anxiety & panic attacks since this happened. pain on the right neck; I'm having more anxiety & panic attacks since this happened. Arthritis; pain on the right arm; pain on the right side of my head; I felt a little strange; I had a low grade fever of 99.9 or 100F; Muscle aches/ Body ache; This spontaneous case was reported by a consumer and describes the occurrence of MULTISYSTEM INFLAMMATORY SYNDROME IN ADULTS (MISA response), PERICARDIAL EFFUSION (Pericardial effusion), CHEST DISCOMFORT (chest tightness), SINUS TACHYCARDIA (sinus tachycardia), DYSPNOEA (shortness of breath) and FLANK PAIN (Flank pain that wrapped around my back & the front of my stomach) in a 49-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 011A21A and 038K20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below. No Medical History information was reported. On 03-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 03-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 03-Mar-2021, the patient experienced PYREXIA (I had a low grade fever of 99.9 or 100F) and MYALGIA (Muscle aches/ Body ache). On 18-Mar-2021, the patient experienced FLANK PAIN (Flank pain that wrapped around my back & the front of my stomach) (seriousness criterion hospitalization) and FEELING ABNORMAL (I felt a little strange). On an unknown date, the patient experienced MULTISYSTEM INFLAMMATORY SYNDROME IN ADULTS (MISA response) (seriousness criterion medically significant), PERICARDIAL EFFUSION (Pericardial effusion) (seriousness criterion medically significant), CHEST DISCOMFORT (chest tightness) (seriousness criterion hospitalization), SINUS TACHYCARDIA (sinus tachycardia) (seriousness criterion hospitalization), DYSPNOEA (shortness of breath) (seriousness criterion hospitalization), NEPHROLITHIASIS (They found 100 tiny kidney stones), BILIARY COLIC (Gallbladder pain), RENAL PAIN (I had kidney pain.), NONINFECTIVE GINGIVITIS (Gums were inflamed), INFLAMMATION (My whole body was inflamed), GASTRITIS (inflammation in my  stomach), OESOPHAGITIS (inflammation in my esophagus.), PANIC ATTACK (I'm having more anxiety & panic attacks since this happened.), NECK PAIN (pain on the right neck), ANXIETY (I'm having more anxiety & panic attacks since this happened.), ARTHRITIS (Arthritis), PAIN IN EXTREMITY (pain on the right arm) and HEADACHE (pain on the right side of my head). The patient was hospitalized from 18-Mar-2021 to 21-Mar-2021 due to FLANK PAIN, then for 2 days due to CHEST DISCOMFORT, DYSPNOEA and SINUS TACHYCARDIA. The patient was treated with PARACETAMOL (TYLENOL [PARACETAMOL]) ongoing from 03-Mar-2021 for Fever, Muscle ache and Ache, at an unspecified dose and frequency and FAMOTIDINE (PEPCID AC) ongoing since an unknown date for Inflammation stomach, at an unspecified dose and frequency. At the time of the report, MULTISYSTEM INFLAMMATORY SYNDROME IN ADULTS (MISA response), PERICARDIAL EFFUSION (Pericardial effusion), CHEST DISCOMFORT (chest tightness), SINUS TACHYCARDIA (sinus tachycardia), DYSPNOEA (shortness of breath), FLANK PAIN (Flank pain that wrapped around my back & the front of my stomach), NEPHROLITHIASIS (They found 100 tiny kidney stones), BILIARY COLIC (Gallbladder pain), RENAL PAIN (I had kidney pain.), NONINFECTIVE GINGIVITIS (Gums were inflamed), INFLAMMATION (My whole body was inflamed), FEELING ABNORMAL (I felt a little strange), GASTRITIS (inflammation in my  stomach), OESOPHAGITIS (inflammation in my esophagus.), PANIC ATTACK (I'm having more anxiety & panic attacks since this happened.), NECK PAIN (pain on the right neck), ANXIETY (I'm having more anxiety & panic attacks since this happened.), ARTHRITIS (Arthritis), PAIN IN EXTREMITY (pain on the right arm), HEADACHE (pain on the right side of my head), PYREXIA (I had a low grade fever of 99.9 or 100F) and MYALGIA (Muscle aches/ Body ache) outcome was unknown.  DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available):On 03-Mar-2021, Body temperature: 99.9f or 100f (High) low grade fever of 99.9F or 100F.On 18-Mar-2021, Computerised tomogram: abnormal (abnormal) pericardial effusion.On 18-Mar-2021, Electrocardiogram: abnormal (abnormal) pericardial effusion.On 18-Mar-2021, Ultrasound scan: abnormal (abnormal) pericardial effusion. In August 2021, Endoscopy: abnormal (abnormal) inflammation in my esophagus & my stomach.. In August 2021, SARS-CoV-2 antibody test: positive (Positive) H 7.69. In October 2021, X-ray: abnormal (abnormal) arthritis.On an unknown date, Rhesus antigen negative: negative (Negative) Negative. Concomitant medications were not reported. The patient reported that, she would keep taking deep breaths, on 18-mar-2021 she had Colitis. Company Comment: This case concerns a 49 year-old female patient with no reported medical history, who experienced the unexpected serious events of Multisystem inflammatory syndrome in adults (AESI), Pericardial effusion, Sinus tachycardia, Dyspnoea, and Flank pain, and the unexpected non-serious AESI of Arthritis. The events occurred  an unknown number of days after the second dose of mRNA-1273 vaccine, except for the event of Flank pain which occurred 15 days after the second dose. Details of the clinical events and chronology of symptoms were not clearly reported for this case. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. This case was linked to MOD-2021-370456 (Patient Link). Sender's Comments: This case concerns a 49 year-old female patient with no reported medical history, who experienced the unexpected serious events of Multisystem inflammatory syndrome in adults (AESI), Pericardial effusion, Sinus tachycardia, Dyspnoea, and Flank pain, and the unexpected non-serious AESI of Arthritis. The events occurred  an unknown number of days after the second dose of mRNA-1273 vaccine, except for the event of Flank pain which occurred 15 days after the second dose. Details of the clinical events and chronology of symptoms were not clearly reported for this case. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.