Suspected frozen shoulder injury related to vaccine administration (SIRVA); Suspected frozen shoulder injury related to vaccine administration (SIRVA); Disruption in her activities of daily living; Subacromial bursitis; Limited shoulder ROM and functional ability; Weakness; Right shoulder pain/pain as localized deep in the shoulder/right-dominant shoulder pain/increasing shoulder pain/Shoulder pain exacerbated with activity, especially lifting, sleeping, and reaching behind back; This literature case was received on 16-Aug-2021 with additional information received on 18-Aug-2021 (being processed together) and concerned a 46-year-old, female patient.   The patient's concurrent conditions included body mass index at 32.5 (high body mass index), otherwise the patient was healthy with no past issues with vaccinations. Her medical and orthopedic histories were unremarkable. The patient was not taking any concomitant medications. The patient had no known allergies.  On an unspecified date, the patient was vaccinated with influenza virus vaccine polyvalent (brand not specified; route of administration, dose and anatomical location: not reported) as a yearly influenza vaccination. The batch number was not reported.  On the same day, within several hours after receiving influenza virus vaccine polyvalent, the patient developed right-dominant shoulder pain described as localized deep in the shoulder anteriorly with weakness and range of motion (ROM) limitations. The pain and ROM limitations slowly progressed over the four months.   On an unspecified date, the patient presented to sport medicine clinic with four months duration right shoulder pain. Increasing shoulder pain, limited shoulder ROM and functional ability, and greater disruption in her activities of daily living necessitated her initial visit. Her shoulder pain was exacerbated with activity, especially lifting, sleeping, and reaching behind her back. On initial examination, the patient had very limited right shoulder ROM and experienced pain with both active and passive ROM. Shoulder deficits on examination demonstrated active flexion to 100°, passive forward flexion to 100°, internal rotation to the level of the sacrum, and passive external rotation to 30°. Pain was elicited with shoulder flexion and extension, but no pain noted with cross-chest adduction or acromioclavicular joint palpation. No motor weakness or scapular winging was noted. No erythema, warmth, or muscle atrophy on inspection. Right shoulder was neurovascular intact, and comparison left shoulder examination was all within normal limits. Anteroposterior radiographs of the right shoulder demonstrated no glenohumeral arthritis and normal joint alignment. Coronal T2-weighted magnetic resonance imaging demonstrated normal deltoid musculature and mild subacromial bursitis with significant inflammation and thickening of the joint capsule and obliteration of the axillary recess, consistent with adhesive capsulitis. The patient was given a glenohumeral joint steroid injection under fluoroscopy with subsequent physical therapy for shoulder ROM to discomfort but not to pain.   On an unspecified date, seven months postvaccination, the patient failed conservative management and underwent shoulder manipulation under anesthesia with excellent results. Scar tissue release was palpated, and full ROM equal to the opposite side was achieved under anesthesia after manipulation.  On an unspecified date, the patient was discharged with a home-exercise physical therapy maintenance program. Her final diagnosis was suspected frozen shoulder injury related to vaccine administration (SIRVA).  On an unspecified date, two months post manipulation, the patient subsequently made improvements with her shoulder ROM and her functional reach. She felt that her ROM and strength allowed her to conduct her desired daily activities.  At the time of initial reporting, the patient was recovering from the events.   The reporter assessed all events as related to influenza virus vaccine polyvalent. The patient had no history of shoulder dysfunction, and the onset of pain with limitation of shoulder ROM developed almost immediately after vaccine administration. The proposed mechanism of injury was attributed to a robust local immune mediated inflammatory response related to vaccine material injected directly into the subdeltoid/subacromial bursa and/or synovial tissue. The presentation of adhesive capsulitis (as demonstrated by the patient's pain, decreased ROM, weakness, and impaired mobility/functionality) with collaborative physical and radiographic findings were all much more than would be expected by the routine trauma of vaccination and were consistent with SIRVA.  All events were assessed as serious due to hospitalisation. Additionally, all events were considered as medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.  In conclusion, this case report should serve as a catalyst for discussion regarding vaccination technique, location, and potential needle overpenetration. The subdeltoid/ subacromial bursa was prone to accidental infiltration in high-deltoid intramuscular vaccinations, causing a severe local immune inflammatory response. This complication could be prevented if the vaccination was administered at the correct site using the correct needle size. A greater understanding of the anatomy and use of the correct intramuscular administration technique was important to prevent this rare postvaccination complication. Practitioners should consider SIRVA as part of the differential diagnosis in patients presenting with acute shoulder pain after vaccine administration.  Company comment: A 46-year-old, female patient developed shoulder pain with associated extremity weakness within several hours after vaccination with the suspect product influenza virus vaccine polyvalent. Symptoms continued for four months leading to decrease in joint range of motion and impaired activities of daily living. Coronal T2-weighted magnetic resonance imaging was performed demonstrating normal deltoid musculature and mild subacromial bursitis with significant inflammation and thickening of the joint capsule and obliteration of the axillary recess, consistent with adhesive capsulitis. As reported the patient's final diagnosis was suspected frozen shoulder injury related to vaccine administration (SIRVA). With lack of confounding factors and considering the diagnostic findings, causality for all reported events is assessed as possibly related.; Reporter's Comments: The patient had no history of shoulder dysfunction, and the onset of pain with limitation of shoulder ROM developed almost immediately after vaccine administration. The proposed mechanism of injury was attributed to a robust local immune mediated inflammatory response related to vaccine material injected directly into the subdeltoid/subacromial bursa and/or synovial tissue. The presentation of adhesive capsulitis (as demonstrated by the patient's pain, decreased ROM, weakness, and impaired mobility/functionality) with collaborative physical and radiographic findings were all much more than would be expected by the routine trauma of vaccination and were consistent with SIRVA.; Sender's Comments: A 46-year-old, female patient developed shoulder pain with associated extremity weakness within several hours after vaccination with the suspect product influenza virus vaccine polyvalent. Symptoms continued for four months leading to decrease in joint range of motion and impaired activities of daily living. Coronal T2-weighted magnetic resonance imaging was performed demonstrating normal deltoid musculature and mild subacromial bursitis with significant inflammation and thickening of the joint capsule and obliteration of the axillary recess, consistent with adhesive capsulitis. As reported the patient's final diagnosis was suspected frozen shoulder injury related to vaccine administration (SIRVA). With lack of confounding factors and considering the diagnostic findings, causality for all reported events is assessed as possibly related.