Arcobacter infection; Cardiac tamponade; COVID-19; This literature-non-study case was reported in a literature article and describes the occurrence of BACTERIAL INFECTION (Arcobacter infection) and CARDIAC TAMPONADE (Cardiac tamponade) in a 32-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.   LITERATURE REFERENCE:     The patient's past medical history included Latent syphilis and Pneumocystis pneumonia. Concurrent medical conditions included HIV disease, End stage renal disease (ESRD) and Hypertension.    On an unknown date, the patient received dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, the patient experienced BACTERIAL INFECTION (Arcobacter infection) (seriousness criterion hospitalization), CARDIAC TAMPONADE (Cardiac tamponade) (seriousness criteria hospitalization and medically significant) and COVID-19 (COVID-19). The patient was treated with MEROPENEM (intravenous) at an unspecified dose and frequency; CIPROFLOXACIN (oral) at an unspecified dose and frequency; COLCHICINE at a dose of low dose; IBUPROFEN at a dose of Tapered dose and Surgery (pericardiocentesis and pericardial drain) for Bacterial infection. At the time of the report, BACTERIAL INFECTION (Arcobacter infection) and CARDIAC TAMPONADE (Cardiac tamponade) had resolved and COVID-19 (COVID-19) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood creatinine: Elevated. On an unknown date, Blood culture: Culture on aerobic blood agar grew Arcobacter spp. of unknown specific species, and blood cultures were also positive for Arcobacter spp.. On an unknown date, C-reactive protein: Elevated. On an unknown date, Cardiac imaging procedure: showed cardiomegaly with pulmonary vascular congestion and diffuse interstitial edema. On an unknown date, Echocardiogram: showed a large circumferential pericardial effusion with tamponade physiology present and showed complete resolution of the pericardial effusion and improved left ventricular function. On an unknown date, Electrocardiogram: Revealed diffuse ST-segment elevation. On an unknown date, Fibrin D dimer: Elevated. On an unknown date, Laboratory test: Showed complete resolution of the pericardial effusion and improved left ventricular function. On an unknown date, SARS-CoV-2 test: Positive. On an unknown date, Troponin: Elevated.     The action taken with mRNA-1273 (Spikevax) (Unknown) was unknown.   For mRNA-1273 (Spikevax) (Unknown), the reporter did not provide any causality assessments.   No concomitant medications were reported.  The patient was and presented with worsening dyspnea, subjective fever, myalgias, cough, pleuritic chest pain, and pericardial rub.  The author highlighted that the potential for Arcobacter spp. to cause severe infections and the importance of considering it as a possible pathogen in patients with atypical presentations.  Company comment: This literature-non-study case concerns a 32-year-old male patient, with relevant medical condition of HIV disease (immunocompromised), who experienced the unexpected and serious (due to hospitalization and medically significant) event of Cardiac tamponade, and the unexpected and serious (due to hospitalization) event of Bacterial infection, which occurred on an unknown date after an unspecified dose of mRNA-1273 vaccine. Since no vaccination, nor events dates were provided, temporal association and latency cannot be properly assessed. As reported, the patient presented with worsening dyspnea, subjective fever, myalgias, cough, pleuritic chest pain, and pericardial rub. Diagnostic workup revealed a positive COVID-19 PCR test, elevated high-sensitive cardiac troponins, elevated C-reactive protein, elevated Ddimer, and elevated creatinine. An ECG revealed diffuse ST-segment elevation, and imaging showed cardiomegaly with pulmonary vascular congestion and diffuse interstitial edema. Urgent transthoracic echocardiogram (TTE) showed a large circumferential pericardial effusion with tamponade physiology present. Culture on aerobic blood agar grew Arcobacter spp. Of unknown specific species, and blood cultures were also positive for Arcobacter spp. Treatment involved intravenous meropenem for five days, followed by oral ciprofloxacin, low-dose colchicine, and a tapered dose of ibuprofen. Repeat laboratory data and TTE showed complete resolution of the pericardial effusion and improved left ventricular function. The company causality for the events was assessed as not related due to lack of biological plausibility. Underlying immunocompromised condition due to HIV remains a risk factor for the case. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.