This spontaneous case was reported by a consumer and describes the occurrence of PERICARDITIS (Pericarditis) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below. The patient's past medical history included COVID-19 (Received a treatment with monoclonal antibodies before receiving her first vaccine.) in August 2021. In November 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In November 2021, the patient experienced ILLNESS (Sick), HYPOTENSION (Low blood pressure), FEELING ABNORMAL (Felt really bad) and DIZZINESS (Dizzy). In January 2022, the patient experienced PERICARDITIS (Pericarditis) (seriousness criterion medically significant). At the time of the report, PERICARDITIS (Pericarditis) was resolving and ILLNESS (Sick), HYPOTENSION (Low blood pressure), FEELING ABNORMAL (Felt really bad) and DIZZINESS (Dizzy) outcome was unknown. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In November 2021, Heart rate: low Low. On an unknown date, Echocardiogram: results not reported Results not reported, improving. The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown. The patient doctor gave some medication and said symptoms will be resolving on 3 weeks. Patient said that now echocardiogram was improving. The doctors administered IV Fluids as treatment. Patient did not want to make a report on this AE and no other information could be gathered on this case. No concomitant medication was reported. Company Comment: This spontaneous case concerns a female patient of unknown age, with a previous history of COVID-19 infection, who experienced an expected, medically significant serious AESI Pericarditis approximately 2 months after her vaccination with first dose of mRNA-1273 vaccine. Exact onset latency of the event Pericarditis could not be established with incomplete start dates of the event and her vaccination. Some medications were given for her pericarditis following her doctor's assessment. The latest echocardiogram report confirmed improvement with her pericarditis. Outcome of the event Pericarditis was reported as resolving. No details regarding risk factors, co morbidities, clinical course, results of labs and diagnostic tests were provided. Previous history of COVID-19 infection remains as a confounder to the event Pericarditis. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement and the available information. Sender's Comments: This spontaneous case concerns a female patient of unknown age, with a previous history of COVID-19 infection, who experienced an expected, medically significant serious AESI Pericarditis approximately 2 months after her vaccination with first dose of mRNA-1273 vaccine. Exact onset latency of the event Pericarditis could not be established with incomplete start dates of the event and her vaccination. Some medications were given for her pericarditis following her doctor's assessment. The latest echocardiogram report confirmed improvement with her pericarditis. Outcome of the event Pericarditis was reported as resolving. No details regarding risk factors, co morbidities, clinical course, results of labs and diagnostic tests were provided. Previous history of COVID-19 infection remains as a confounder to the event Pericarditis. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement and the available information.