Abstract Background As the number of individuals receiving the Covid-19 Vaccine continues to rise, we have observed a concurrent increase in myopericarditis cases within the general population. This case serves as a reminder of the necessity to approach such occurrences with an open mind. Additionally, it underscores the importance of employing multi modal imaging techniques alongside a collaborative, multidisciplinary approach when addressing complex medical cases. Case Summary We present a case of a woman in her fifties attending the emergency department with pyrexia, lethargy and chest pain following the AstraZenca COVID-19 vaccine. She had a background of systemic lupus erythematosus which was treated with immunosuppressive medication. Initial assessments revealed abnormal ECG, elevated troponin and raised inflammatory markers. A diagnosis of likely vaccine induced myopericarditis was made. However, blood cultures revealed Listeria monocytogenes and cardiac imaging confirmed a Right Atrial (RA) thrombus which, was considered to be infected. Subsequently, she was treated for Listeria myopericarditis and infected thrombus with intravenous antibiotics and anticoagulation. The patient did not wish for any invasive investigations given her clinical improvement. This is the first case of Listeria-related myopericarditis with an infected thrombus in the right atrium. We saw full resolution of RA mass with medical management. Discussion This case highlights the importance of multimodality imaging techniques to facilitate the diagnosis of listeria related myopericarditis accompanied by an infected thrombus. It also emphasises the importance of conducting interval scanning and follow-up assessments to ensure resolution of the disease. To improve diagnostic accuracy a Endomyocardial biopsy can also be considered.