Arthroscopic debridement for acute hemorrhagic subacromial bursitis; generalized malaise; low-grade fevers; erroneous vaccine injection location; This literature-non-study case was reported in a literature article and describes the occurrence of BURSITIS (Arthroscopic debridement for acute hemorrhagic subacromial bursitis) in a 26-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.       Concurrent medical conditions included Nonsmoker.    On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular use) 1 dosage form. On an unknown date, the patient experienced BURSITIS (Arthroscopic debridement for acute hemorrhagic subacromial bursitis) (seriousness criterion hospitalization). an unknown date, the patient experienced MALAISE (generalized malaise) and PYREXIA (low-grade fevers). an unknown date, the patient experienced PRODUCT ADMINISTERED AT INAPPROPRIATE SITE (erroneous vaccine injection location). The patient was hospitalized for 3 days due to BURSITIS. The patient was treated with CELECOXIB at a dose of 200 milligram twice a day and Surgery (arthroscopic decompression of subacromial bursitis) for Bursitis. At the time of the report, BURSITIS (Arthroscopic debridement for acute hemorrhagic subacromial bursitis), MALAISE (generalized malaise) and PYREXIA (low-grade fevers) had resolved and PRODUCT ADMINISTERED AT INAPPROPRIATE SITE (erroneous vaccine injection location) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Arthroscopy: subacromial bursitis, Intra-operative arthroscopic image: Hemorrhagic bursitis of the subacromial space and Intra-operative arthroscopic image: Post-bursectomy, shoulder with no evident rotator cuff pathology; normal appearance  of supraspinatus tendon. On an unknown date, C-reactive protein: 1.2 mg/dl elevated. On an unknown date, Full blood count: There were no other significant abnormalities on blood count. On an unknown date, Imaging procedure: Right shoulder AP radiograph (three view plain radiographs) did not demonstrate any acute abnormality. On an unknown date, Magnetic resonance imaging joint: Right shoulder T2 coronal MRI: A trace subacromial subdeltoid effusion with adjacent synovial thickening. Intact rotator cuff and no intraarticular pathology.. On an unknown date, Metabolic function test: There were no other significant abnormalities on metabolic panel. On an unknown date, Physical examination: Skin was intact with minimal swelling or erythema of his right shoulder. There was evidence of a prior vaccine injection site lateral to the edge of the acromion. The shoulder was exquisitely tender to palpation along the sub-deltoid bursa.  Severe pain with all motion and able to actively forward flex less than 10 degrees.   Able to internally rotate to his abdomen and externally rotate to neutral.  Positive Neer's and Jobe's test and An examination under anesthesia was performed which demonstrated full range of motion. On an unknown date, Red blood cell sedimentation rate: 5.0 mm/hr Normal. On an unknown date, Vital signs measurement: Stable. On an unknown date, White blood cell count: 7500/uL Normal.     mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular use) dosing remained unchanged.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular use), the reporter considered BURSITIS (Arthroscopic debridement for acute hemorrhagic subacromial bursitis), MALAISE (generalized malaise) and PYREXIA (low-grade fevers) to be related. No further causality assessment was provided for PRODUCT ADMINISTERED AT INAPPROPRIATE SITE (erroneous vaccine injection location).    The patient presented to emergency department (ED) with a 48hr history of acute onset right shoulder pain that began several hours after receiving first dose of Moderna vaccination. The pain was located over the superolateral aspect of his right shoulder without radiation. It was dull, constant, and exacerbated by movement. Pain was increasingly severe, limiting his function and sleep. No numbness, weakness, or paresthesia in the affected extremity. No history of shoulder injuries and no antecedent shoulder pain. He consulted with his primary care physician, who referred him to ED for further evaluation. At the time of the initial vaccination, the patient felt the injection site had been "too high" up on his arm. Location that was just 1 cm distal to the lateral edge of the acromion. The patient was otherwise healthy without any pertinent medical, surgical, or family history. He did not take any medication regularly. On arrival to the ED he was afebrile.  Postoperatively, he had nearly complete resolution of his pain by following day. On postoperative day 1, consisting of active and active-assisted shoulder range of motion (ROM) without restriction. He achieved functional ROM from 0-120 degrees with occupational therapy. He was discharged home in improved condition. Treatment also included non-steroidal anti-inflammatory and standard multimodal pain medications.  His first postoperative visit, he had recovered well. He achieved full, painless ROM and strength in his right shoulder. No signs of fevers or chills. All sutures were removed, and the incisions were healing well without signs of infection. He was cleared for all activity as tolerated at that time at subsequent follow-up six weeks after surgery, he continued to recover well. He returned to all activity without pain in his right shoulder and did not have any further signs of infection. He elected to have second vaccination dose administered in the contralateral shoulder, which occurred without incident.  Company Comment: This literature non study case concerns a 26-year-old male patient, with no relevant medical history reported, who experienced the unexpected serious (hospitalization) event of BURSITIS, 48 hours after the first dose of mRNA-1273 (Moderna COVID-19 Vaccine). He experienced right shoulder pain that began several hours after vaccination without radiation and with any numbness, weakness, or paresthesia in the affected extremity. In addition, he had low-grade fevers and generalized malaise the day following his vaccine. On arrival he was afebrile with stable vital signs. On exam, the skin was intact with minimal swelling or erythema of his right shoulder and was exquisitely tender to palpation along the sub-deltoid bursa. He had severe pain with all motion and was able to actively forward flex less than 10 degrees. There was a positive Neer's and Jobe's test. His laboratory workup was significant for C-reactive protein of 1.2 mg/dL (elevated) but no other significant abnormalities on his blood count or metabolic panel. Imaging workup of the right shoulder included radiographs which did not demonstrate any acute abnormality. Subsequent imaging with an MRI demonstrated a trace subacromial-subdeltoid effusion with adjacent synovial thickening with no evidence of rotator cuff injury and no other acute abnormality on imaging. An arthroscopic debridement of the subacromial bursa and subacromial decompression were performed in the operating room with nearly complete resolution of his pain the next day. Celecoxib 200 mg twice daily for 14 days in addition to standard multimodal pain medications was prescribed at discharged on the third day. Two weeks after surgery, he recovered well and returned to all activity without pain in his right shoulder. An erroneous vaccine injection location was also reported: only 1 cm distal to the lateral edge of the acromion. No further clinical information was available for medical review. The benefit-risk relationship of mRNA-1273 (Moderna COVID-19 Vaccine) is not affected by this report.