Empyema (Puss); Large abscess forming in the deep portion of the left side of his neck; Under his armpit the lymph nodes were swollen and hard.; Fever/ low grade fever; Malaise; Uncomfortable; Body aches; This spontaneous case was reported by an other health care professional and describes the occurrence of EMPYEMA (Empyema (Puss)) and ABSCESS NECK (Large abscess forming in the deep portion of the left side of his neck) in a 47-year-old male 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 18-Nov-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 19-Nov-2021, the patient experienced MALAISE (Malaise), DISCOMFORT (Uncomfortable), MYALGIA (Body aches) and PYREXIA (Fever/ low grade fever). On 26-Nov-2021, the patient experienced EMPYEMA (Empyema (Puss)) (seriousness criteria hospitalization and medically significant), ABSCESS NECK (Large abscess forming in the deep portion of the left side of his neck) (seriousness criterion hospitalization) and LYMPHADENOPATHY (Under his armpit the lymph nodes were swollen and hard.). The patient was hospitalized on 26-Nov-2021 due to ABSCESS NECK and EMPYEMA. The patient was treated with Surgery (chest surgery for the infection) for Empyema and Surgery (Drainage) for Abscess neck. At the time of the report, EMPYEMA (Empyema (Puss)), ABSCESS NECK (Large abscess forming in the deep portion of the left side of his neck), MALAISE (Malaise), DISCOMFORT (Uncomfortable), MYALGIA (Body aches), LYMPHADENOPATHY (Under his armpit the lymph nodes were swollen and hard.) and PYREXIA (Fever/ low grade fever) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 19-Nov-2021, Body temperature: fever (High) Low grade fever. On 23-Nov-2021, Body temperature: fever (High) Fever. On 26-Nov-2021, Computerised tomogram thorax: abnormal (abnormal) CT scan of chest and neck showed-Large abscess forming in the deep portion of the left side of his neck, where the swollen lymph nodes were adjacent to his spine. The abscess was communicating to the left lung and caused empyema (puss).. On 26-Nov-2021, Laboratory test: abnormal (abnormal) Abnormal.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Concomitant medication were not provided  Patient was treated with aggressive antibiotics when patient was admitted to the hospital.   Company comment : This case concerns a  47-year-old, male patient with no relevant medical history, who experienced the serious unexpected events Abscess Neck and empyema. The events occurred approximately 8 days after the booster dose of mRNA-1273. Patient had a large abscess forming in the deep portion of the left side of his neck. The abscess was communicating to the left hemithorax and caused empyema. Patient was admitted to hospital  and was treated with antibiotics and surgery to drain out abscess and empyema. The benefit-risk relationship of mRNA-1273 (Moderna covid-19 vaccine) is not affected by this report.  Nurse Practitioner on behalf of his husband reported that patient had received his booster dose. On 23-NOV-2021 patient also had fever. On 26-NOV-2021 patient had went to Emergency Department for evaluation. Patient had chest surgery for infection where they opened up patients left lung to clean up and drain infection and they also made an incision in his neck to drain out abscess. Patient was currently recovering in hospital. Patient had tubes coming out of his chest and drains coming out of his neck. Nurse practitioner did not felt the vaccine had anything to do with abscess but was wondered if the mRNA in the vaccine created a strong signaling immune response to alert the body that there was an abscess.; Sender's Comments: This case concerns a  47-year-old, male patient with no relevant medical history, who experienced the serious unexpected events Abscess Neck and empyema. The events occurred approximately 8 days after the booster dose of mRNA-1273. Patient had a large abscess forming in the deep portion of the left side of his neck. The abscess was communicating to the left hemithorax and caused empyema. Patient was admitted to hospital  and was treated with antibiotics and surgery to drain out abscess and empyema. The benefit-risk relationship of mRNA-1273 (Moderna covid-19 vaccine) is not affected by this report.