lethargy; POTS (Postural Orthostatic Tachycardia Syndrome); pericarditis; This spontaneous case was reported by a consumer and describes the occurrence of PERICARDITIS (pericarditis) in a 19-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On 23-Jul-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 20-Aug-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In September 2021, the patient experienced PERICARDITIS (pericarditis) (seriousness criterion medically significant). In May 2022, the patient experienced POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (POTS (Postural Orthostatic Tachycardia Syndrome)). On an unknown date, the patient experienced LETHARGY (lethargy). The patient was treated with MIDODRINE HYDROCHLORIDE (MIDODRIN) for Postural orthostatic tachycardia syndrome, at a dose of 3 times a day. In October 2021, PERICARDITIS (pericarditis) had resolved. At the time of the report, LETHARGY (lethargy) and POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (POTS (Postural Orthostatic Tachycardia Syndrome)) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Electrocardiogram: EKG was done at one point and she was told that she had inflammation and fluid around the heart..     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered PERICARDITIS (pericarditis) to be related. No further causality assessments were provided for LETHARGY (lethargy) and POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (POTS (Postural Orthostatic Tachycardia Syndrome)).    Patient was diagnosed with pericarditis at the beginning of Sep2021. EKG was done at one point and she was told that she had inflammation and fluid around the heart. She was also diagnosed to have POTS (Postural Orthostatic Tachycardia Syndrome) by an electrophysiologist last May2022 - since she was still having the symptoms after 6 months. She was given an anti-inflammatory drug for her pericarditis and was put on a heart monitor.  Patient had no allergies, not had COVID and related test. Patient had no acute and chronic illness at the time of vaccination. Patient had no other vaccines given within 1 month prior to Moderna COVID-19 vaccine. Patient had not experienced event similar in past. The symptoms of pericarditis included angina pectoris, fluid around the heart, dyspnoea at rest, chest discomfort, chest pain, musculoskelatal chest pain, dyspnoea, dyspnoea exertional, palpitations and inflammation and fluid around the heart. The symptom of Postural Orthostatic Tachycardia Syndrome included syncope.  Company comment: This is a spontaneous case concerning a 19 year-old, female patient with no previous medical history, who experienced the serious (due to medically important condition) expected, AESI of pericarditis and the non serious AESI of Postural orthostatic tachycardia syndrome (POTS). The event pericarditis occurred the month after the second dose of mRNA-1273 vaccine and the event Postural orthostatic tachycardia syndrome, 9 months after vaccination. The patient reported the following symptoms angina pectoris, pericardial effusion, dyspnoea at rest, chest discomfort, chest pain, dyspnoea, dyspnoea exertional and palpitations. Electrocardiogram was reported as inflammation and fluid around the heart. Patient had an urgent care visit but wasn´t hospitalized. Patient received treatment with midodrine hydrochloride for POTS and anti-inflammatory medication for pericarditis. The outcome of the event pericarditis was reported as recovered with 1 and a half month duration and the event Postural orthostatic tachycardia as not resolved. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: Company Comment: This is a spontaneous case concerning a 19 year-old, female patient with no previous medical history, who experienced the serious (due to medically important condition) expected, AESI of pericarditis and the non serious AESI of Postural orthostatic tachycardia syndrome (POTS). The event pericarditis occurred the month after the second dose of mRNA-1273 vaccine and the event Postural orthostatic tachycardia syndrome, 9 months after vaccination. The patient reported the following symptoms angina pectoris, pericardial effusion, dyspnoea at rest, chest discomfort, chest pain, dyspnoea, dyspnoea exertional and palpitations. Electrocardiogram was reported as inflammation and fluid around the heart. Patient had an urgent care visit but wasn´t hospitalized. Patient received treatment with midodrine hydrochloride for POTS and anti-inflammatory medication for pericarditis. The outcome of the event pericarditis was reported as recovered with 1 and a half month duration and the event Postural orthostatic tachycardia as not resolved. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.