Difficulty sleeping on the effected left side; Limitations participating in home improvement projects involving overhead activities / decreased range of motion in all planes; Persistent pain to the left shoulder; Cutibacterium acnes (C. acnes) infection; Activity-related pain / night pain; Shoulder weakness; Shoulder Injury Related to Vaccine Administration (SIRVA); This literature case was received on 02-Oct-2023, and concerned a 33-year-old, female patient.  The purpose of this manuscript is to raise awareness of potential coexistence of SIRVA and Cutibacterium acnes which may be of assistance to surgeons treating refractory cases of SIRVA. The aim of this study is to provide a provisional framework for the workup and treatment of patients with Shoulder Injury Related to Vaccine Administration (SIRVA) and to raise the possibility of infection as a concomitant condition in the presence of refractory SIRVA.  Clinical case files were reviewed for 3 cases of SIRVA with positive cultures for C. acnes were reviewed. Presentation, treatment, and clinical outcomes were compared.  The patient's medical history and concomitant medications were not reported.  On an unspecified date in Sep-2020, the patient was vaccinated with influenza vaccine (brand not specified; anatomical location: left upper arm (reported as 'very high at the edge of the bone on top of my shoulder'); dose, route of administration and indication: not reported). The batch number was not reported.  On the same date, immediately after receiving the influenza vaccine, the patient experienced increasing left shoulder pain.  On an unspecified date in Sep-2020, an unknown amount of time after receiving the influenza vaccine, the patient experienced shoulder weakness, activity-related pain and night pain.  On an unspecified date in Sep-2020, 4 days after receiving the influenza vaccine, the patient first sought medical care, and was presented to a surgical office after a period of observation with no improvement. At presentation, pain was rated as 8 - 9/10 Visual Analogue Scale (VAS), and was associated with decreased range of motion in all planes, with Initial Single Assessment Numeric Evaluation (SANE) score of 20/100.  On an unspecified date in May-2021, after eight months of persistent shoulder pain and weakness despite a small improvement around 4-5 months from injection followed by return and progression of symptoms, the patient first obtained a magnetic resonance imaging (MRI) which revealed increased signal in the subacromial bursa without associated bony edema.  On an unspecified date in 2021, three weeks following the MRI, arthroscopic irrigation and debridement with harvest of tissue biopsies from the subacromial space of the subacromial bursa harvested with a meniscal punch was performed. Intraoperative cultures grew out C. acnes from the subacromial bursa specimens.  On an unspecified date in 2021, the patient was placed on six months of oral antibiotic therapy with amoxicillin and underwent extensive physical therapy.  On an unspecified date, seven months post operation, as reported, the patient reported SANE score of 90/100, as well as persistent pain to the left shoulder, continued difficulty sleeping on the effected left side, and limitations participating in home improvement projects involving overhead activities.  The outcome of the events of loss of shoulder injury related to vaccine administration, Cutibacterium acnes infection, pain, difficulty sleeping, mobility decreased, weakness of upper extremities, and shoulder pain was not reported.  The reporter did not provide a causality assessment.  All events were considered to be medically significant by Physician within CSL Seqirus' Pharmacovigilance and Risk Management Department.  In all cases, patients were thin (body mass index < 23), females, who had high injection placement of a vaccine, all patients had positive magnetic resonance imaging indings of increased signal in the subacromial bursa, and/or greater tuberosity. All patients underwent arthroscopic débridement and culture harvest and cultures were positive for C. acnes. A combination of oral and intravenous antibiotics was used, and all patients demonstrated clinical improvement from the preoperative state.  Based on available case reports and limited data, surgeons may consider the possibility of C. acnes positivity in the workup and treatment of persistent shoulder pain after vaccine administration. A history of small body habitus, high injection site location, pain at rest or with sleep, and loss of shoulder motion and strength should raise an index of suspicion for advanced imaging and, in select cases, arthroscopy with harvest of tissue cultures and concomitant arthroscopic debridement.  This case is linked with case 202304460 (the same literature article).  Company comment: A 33-year-old, female patient was vaccinated with the suspect product influenza vaccine. On the same day after vaccination the patient experienced increasing left shoulder pain. Within the same month the patient experienced shoulder weakness, activity-related pain and night pain. Following MRI evaluation, arthroscopic irrigation and debridement with harvest of tissue biopsies from the subacromial space of the subacromial bursa harvested with a meniscal punch was performed. Intraoperative cultures grew out C. acnes from the subacromial bursa specimens. Information regarding the underlying medical history and concomitant medications has not been provided. Although influenza vaccine as active ingredient may have not led to the development of bacterial infections, the vaccine administration procedure may have put the patient under risk. Causality for the event Cutibacterium acnes infection is therefore assessed as possibly related. Causality for the remaining events shoulder injury related to vaccine administration, pain, difficulty sleeping, mobility decreased, muscular weakness and arthralgia is assessed as possibly related based on plausible temporal relationship.; Sender's Comments: A 33-year-old, female patient was vaccinated with the suspect product influenza vaccine. On the same day after vaccination the patient experienced increasing left shoulder pain. Within the same month the patient experienced shoulder weakness, activity-related pain and night pain. Following MRI evaluation, arthroscopic irrigation and debridement with harvest of tissue biopsies from the subacromial space of the subacromial bursa harvested with a meniscal punch was performed. Intraoperative cultures grew out C. acnes from the subacromial bursa specimens. Information regarding the underlying medical history and concomitant medications has not been provided. Although influenza vaccine as active ingredient may have not led to the development of bacterial infections, the vaccine administration procedure may have put the patient under risk. Causality for the event Cutibacterium acnes infection is therefore assessed as possibly related. Causality for the remaining events shoulder injury related to vaccine administration, pain, difficulty sleeping, mobility decreased, muscular weakness and arthralgia is assessed as possibly related based on plausible temporal relationship.