An analysis of reported cases shoulder injury related to vaccine administration of after COVID-19 vaccination

ABSTRACT

To prevent COVID-19, the COVID-19 vaccine has been widely administered worldwide, but various complications accompany this vaccine. The aim of this study was to investigate the demographic patterns, clinical features, diagnostic findings, and treatment outcomes associated with shoulder injury related to vaccine administration (SIRVA). This study examined 22 patients with SIRVA following COVID-19 vaccination from the Web of Science (WOS) and PubMed databases. The patients were categorized based on sex, age, type of COVID-19 vaccine received, dose administered, latency of symptom onset, and the presence of specific clinical manifestations. Patients, evenly distributed by sex (12 females, 10 males), and aged 21 to 84 years (mean age 46.6), were analyzed. SIRVA cases were reported across all age groups. The Pfizer – BioNTech COVID-19 vaccine had the highest incidence (n = 8), followed by the Oxford/AstraZeneca COVID-19 vaccine (n = 4). Symptoms, primarily shoulder pain (n = 22) and shoulder mobility disorders (n = 18), occurred within three days post-vaccination. Some patients also reported shoulder swelling (n = 5) and fever (n = 2). Imaging revealed nonspecific X-ray findings, supraspinatus tendon calcification (n = 2), and shoulder edema and inflammation on MRI (n = 12). This study provides insights into the clinical aspects of SIRVA related to COVID-19 vaccination. Recognition and appropriate management of these complications are crucial for optimal patient outcomes.

GRAPHICAL ABSTRACT

Injury mechanism of SIRVA. The three main causes of SIRVA.

KEYWORDS:

• SIRVA
• COVID-19 vaccine
• shoulder injury
• clinical characteristics
• treatment outcomes

Introduction

Since the COVID-19 pandemic began, countries around the world have gradually completed vaccination against COVID-19, though this way followed by side effects, including fever and local pain. As the number of people vaccinated gradually increased, more SIRVA patients were reported.^1–3

SIRVA refers to shoulder pain and rigidity within hours after vaccine injection, due to incorrect injection of the vaccine into the shoulder joint bursa instead of the deltoid muscle. Moreover, because of improper muscle injection, unsuitable syringe selection or incorrect selection of the injection site, all the reasons above will cause accidental injection of the vaccine into the joint capsule below the deltoid muscle and its surroundings. Finally, inflammation is induced, even injuring the skeletal muscle system of the shoulder.⁴

Currently, there is no systematic diagnosis or treatment plan for SIRVA, and treatment relies mostly on nonsteroidal anti-inflammatory agent (NSAID) drugs and glucocorticoids; moreover, some patients with combined tendon and bone injuries may require further surgical treatment. Therefore, how to effectively prevent SIRVA is particularly important.⁵

In this study, we focused on analyzing reported SIRVA cases and contributing to the standardization of COVID-19 vaccine injection.

Method

Strategies

We used the Web of Science (WOS) database to obtain SIRVA patient information that appeared after COVID-19 vaccine injection without any restrictions. The search strategies used were as follows: TS = (“Covid-19 vaccine” OR “Coronavirus vaccine” OR “COVID-19 vaccination” OR “Coronavirus vaccination” OR “Covid-19 vaccinate” OR “Coronavirus vaccinate”) AND TS = (“Shoulder Injury” OR “Shoulder Pain” OR “SIRVA”). Moreover, the paper type was limited to “case reports.” The same strategies were applied in PubMed. Finally, duplicate and studies were excluded, as some patients with myocarditis after injection of the COVID-19 vaccine had clinical manifestations of shoulder pain, causing errors; the procedure is shown in Figure 1. Inclusion criteria: 1. SIRVA related to COVID-19 vaccine. 2. Paper type is “case reports.” 3. Language limits to English. Exclusion criteria: Shoulder pain caused by other complications after injection of COVID-19 vaccine, without primary focus on the shoulder.

Figure 1. Procedure of screening studies. After searching, screening and including total of 18 case reports were included.

Study choices

After deleting duplicate and unrelated literature, we obtained a total of 16 articles and 19 cases. The following information was collected from these patients: 1. patient age; 2. sex; 3. vaccine type; 4. vaccine dose; 5. when symptoms appeared; 6. laboratory examination; 7. imaging examination; 8. treatment, and 9. outcomes. The data are shown in Tables 1 and 2.

Table 1. Information of selected cases. Here, we summarized the basic information, vaccine information, physical examination, laboratory examination, imaging examination, treatment, and outcome of each case.

No.	Age	Gender	Vaccine Type	Dose	When Symptoms Appeared	Etiology	Physical examination	Laboratory Examination	Imaging Examination	Treatment	Outcome
1^Citation6	84	Female	COVID-19 mRNA vaccination	First	Three days after receiving vaccination	Wrong injection site	Severe tenderness at the left shoulder with moderately sized effusion and limited active range of motion.	White cell count of 10.0 × 103/uL and CRP of <0.6 mg/L.	X-rays showed soft tissue swellings over the deltoid region with no other significant findings. MRI showed chronic near-complete rotator cuff tears of the supraspinatus and infraspinatus with muscle atrophy.	Provide symptomatic treatment and rehabilitation therapy particularly progressive range of motion exercises.	Six weeks and three months after discharge, inspection showed that the pain disappeared, the shoulder joint effusion subsided, and the shoulder joint range of motion was normal.
2^Citation1	21	Male	Pfizer-BioNTech COVID-19 vaccination	First	Fifteen hours after receiving vaccination	Not record	Swelling sensation in the armpit, mild swelling in the neck lymph nodes, and mild tenderness in the injection area.	Not record	MRI showed secondary deltoid edema and mild inflammation in the axillary area.	Not record	Recurred
3^Citation1	26	Female	Pfizer-BioNTech COVID-19 vaccination	First	Four days after receiving vaccination	Not record	Mild shoulder pain only.	Not record	MRI showed edema in the deltoid and quadriceps regions, and lymph node enlargement near the armpit and quadriceps muscles.	Not record	On 1 month follow-up, she again reported no axillary swelling or any deltoid pain.
4^Citation1	34	Female	Pfizer-BioNTech COVID-19 vaccination	Second	Five days after receiving vaccination	Not record	Mild shoulder pain and limited mobility.	Not record	MRI showed deltoid edema and axillary lymph node enlargement.	Not record	All the above symptoms disappeared in the last follow-up examination
5^Citation2	42	Male	Moderna’s mRNA 1273 vaccine	First	Within two days	Wrong injection site	Severe left shoulder pain (numerical pain rating scale of 10/10) and severe limited range of motion.	Not record	MRI showed left shoulder subacromial deltoid bursitis	One course of oral prednisolone	After a few days, the symptoms disappeared, and after two months, the bursitis disappeared
6^Citation2	38	Male	Pfizer-BioNTech COVID-19 vaccination	Second	Two weeks after receiving vaccination	Ambiguity	Severe left shoulder pain (numerical pain rating scale of 10/10) and severe limited range of motion.	Not record	Ultrasound of the left shoulder was performed in which subacromial subdeltoid bursitis was detected	Conservative treatment	The symptoms almost completely resolved by conservative management in less than a week.
7^Citation3	45	Female	Oxford AstraZeneca vaccine	Second	Three days after receiving vaccination	Ambiguity	Moderate shoulder pain and limited range of motion and low-grade fever.	Fluid from the left shoulder joint was aspirated by guided ultrasound guided and pus discharge was reported with fluid analysis showing a white blood cell count of 221,550 cells/mm3, monocytes 2%, polymorphonuclear neutrophils 98%, red blood cell count 35,700 cells/108 mm3, and no crystals. Other fluid was sent for gram stain which showed a few gram-positive cocci pairs and numerous polymorphonuclear neutrophils and a fluid culture showed Staphylococcus aureus. Laboratory studies showed a white blood cell (WBC) count of 15,750 cells/μL (4500–10,000 cells/μL), PMN 77%, eosinophils 0.5%, basophils 0.3%, lymphocytes 15.9%, monocytes 6.3%, an erythrocyte sedimentation rate of 96 mm/h (0–15 mm/h), and C-reactive protein of 202.24 mg/dL (0–5 mg/L).	Radiographs showed no bony pathology in both anteroposterior and lateral transcapular views.	Treated with combined arthroscopic debridement and intravenous ceftriaxone 2 g every 24 h for 7 days.	Her clinical symptoms improved a few days after the arthroscopic surgery. Her fever resolved 2 days after the surgery, her other symptoms within a further few days, and she was discharged at 7 days post-surgery with improved pain but still some limitations in range of motion. She had attained full range of motion 4 weeks after the surgery.
8^Citation7	26	Male	Moderna mRNA COVID-19 vaccination	First	Twenty-four hours after receiving vaccination	Wrong injection site	There is slight swelling on the right shoulder, and there is a vaccine injection site on the outer edge of the shoulder peak. Severe pain during shoulder joint activity, limited forward and lateral rotation movement	White blood cells count of 7500/uL (normal), erythrocyte sedimentation rate of 5.0 mm/hr (normal), and C-reactive protein of 1.2 mg/dL (elevated).	No obvious abnormalities were found on the X-ray, and MRI showed small amount of subacromial deltoid effusion with adjacent synovial thickening	Surgical treatment, postoperative rehabilitation treatment, and oral administration of celecoxib after discharge	Two weeks of follow-up after discharge, the patient’s shoulder joint pain disappeared, and their range of motion and strength were normal
9^Citation8	49	Male	Not record	Not record	Twenty-four hours after receiving vaccination	Practitioners are unprofessional	Severe tenderness of the deltoid muscle, extensive tenderness of the left glenoid shoulder joint, diffuse pain with lateral chest abduction.	Not record	Radiographs of the left shoulder obtained in the ED demonstrated mild acromioclavicular joint osteoarthritis. MRI showed of the left shoulder demonstrated osseous edema within the posterolateral proximal humerus and humeral greater tuberosity at the level of the infraspinatus tendon insertion. Soft tissue edema was also seen within the teres minor tendinous insertion and subscapularis musculotendinous junction. Tearing of the posterosuperior and posterior glenoid labrum with a large paralabral cyst was noted.	A therapeutic injection of 40 mg triamcinolone acetonide was administered via posterior approach into the subacromial bursa with the intent of providing symptom relief.	Six months following the therapeutic shoulder injection, the patient reported no significant improvement in his symptoms that continued to negatively impact his daily life at work and when trying to sleep.
10^Citation9	40	Male	Pfizer COVID vaccine	Second	Two days after receiving vaccination	Ambiguity	Examination of the left shoulder revealed loss of external rotation, internal rotation, abduction, adduction, and forward flexion. Both active and passive movements were affected, and pain in the passive movement was noted.	Not record	X-ray showed subchondral lucency and periarticular sclerosis. MRI confirmed the diagnosis of AVN with associated fragmentation of the humeral head and an underlying subchondral fracture	Perfusion dilation of shoulder joint.	The patient was followed up at one week via telephone and at six weeks face to face. The treatment has improved the range of motion, but significant pain was still present. On examination, he had a positive impingement test and a positive glenohumeral stress test.
11^Citation10	52	Female	Oxford/AstraZeneca COVID-19 vaccine	Not record	Twenty-four hours after receiving vaccination	Inappropriate syringe selection	The passive and active abduction of the left shoulder is significantly reduced compared to the right shoulder, with limited flexion and internal and external rotation of the left shoulder joint.	Not record	MRI showed thickening of synovial sac with mild adhesive cystitis.	non-steroidal anti-inflammatory drugs and physical therapy.	Satisfactory treatment effect.
12^Citation11	51	Female	Oxford-AstraZeneca COVID-19 vaccine	Not record	Three hours after receiving vaccination	Wrong injection site	Physical examination showed tenderness over the deltoid area, with limited range motion of her right shoulder in all directions.	Not record	Radiographs of the anteroposterior and lateral transcapular views of the right shoulder showed soft tissue swelling without fracture. The humeral head was displaced inferiorly with a widened acromiohumeral distance which could have been from joint effusion or distended subacromial-subdeltoid bursa. The greater tuberosity showed cortical irregularities and subcortical sclerosis. Ultrasonography of the right shoulder showed subacromial-subdeltoid bursitis with synovial wall thickening, and internal septa, tenodesis with small full-thickness tear at the posterior fiber of supraspinatus	She was treated with oral NSAIDs.	Her clinical symptoms gradually improved over the next few days.
13^Citation12	83	Female	Pfizer-BioNTech COVID-19 vaccination	First	Not record	Not record	Significant swelling and pain in the shoulders, accompanied by low fever	A blood test revealed elevated C-reactive protein (CRP) of 4.72 mg/dL. Calcium and phosphorus levels were within normal limits at 9.5 mg/dL and 4.0 mg/dL, respectively.	X-rays showed calcification of the supraspinatus tendon.	Regular use of celecoxib and necessary acetaminophen treatment for patients.	Calcification disappeared, left shoulder pain improved, and the range of motion during flexion and abduction was 170 ◦.
14^Citation13	61	Female	Oxford-AstraZeneca, Serum Institute of India	First	Thirty minutes after receiving vaccination	Wrong injection site	Severe pain and limited mobility with active painful arc (45° of abduction, 20° of extension, 45° of flexion). Neer’s, Hawkins,’ Yocum’s, and O’Brien’s tests were positive, while Jobe’s and Patte’s tests were negative.	Not record	X-ray showed no obvious abnormalities, MRI and ultrasound examination supported subacromial deltoid bursitis and rotator tendon disease.	Treatment includes ice packs, topical diclofenac cream, as well as a combination of coffee, diisopropyl alcohol, diclofenac sodium, and acetaminophen. To preserve the range of motion, in an attempt at minimizing potential complications, the patient received prednisone and vitamin D combined with physical therapy.	Not record
15^Citation14	55	Female	Pfizer – BioNTech COVID-19 vaccination	Not record	Several hours after receiving vaccination	Inappropriate syringe selection	Severe shoulder pain (visual analogue scale 10/10) and limited range of motion.	Not record	Radiographs (anteroposterior, scapula Y) of her left shoulder were performed and did not provide helpful diagnostic information. MRI showed subacromial subdeltoid bursitis.	The patient was started on an oral anti-inflammatory drug, and the left subacromial space was injected with 2.5 mg betamethasone with 3 ml of 1% lidocaine without epinephrine every two weeks. One month after starting this treatment, her shoulder pain had not improved, so the oral anti-infammatory drug was switched to tramadol hydrochloride acetaminophen.	Shoulder pain was still significant and affected her daily life.
16^Citation15	52	Male	Sinovac COVID-19 vaccination	Not record	Three days after receiving vaccination	Inappropriate syringe selection	Physical examination showed swelling at the right deltoid area, with limited range of right shoulder motion.	The initial laboratory investigations were white blood cell count 7160/μL, hematocrit 38.0%, hemoglobin 12.8/dL, polymorphonuclear neutrophils 65.2%, lymphocytes 16.9%, eosinophils 13.4%, monocytes 4.2%, platelets 273,000/μL, ESR 9 mm/hr and CRP 3.5 mg/L. The joint fluid analysis showed white blood cell count 45,500 cells/mm3, monocytes 1%, polymorphonuclear neutrophils 99%, red blood cell count 23,400 cells/mm3, and no crystal. No organisms were found in joint fluid by in the gram stain and culture evaluations.	Anteroposterior and lateral radiographic images of the shoulder showed degenerative change without fracture. Patient was sent for ultrasonography which showed subacromial-subcoracoid subdeltoid bursitis.	He was admitted for an intravenous cefazolin (4000 mg/day) for 3 days then changed to oral cefalexine (1000 mg/day) for 7 days.	His clinical symptoms gradually improved. He had no fever after 1 day of admission. He could slowly increase movement in his right shoulder and was able to tolerate passive motion of his right shoulder after 3 days.
17^Citation16	26	Female	Covaxin	Second	15 days after receiving vaccination	Ambiguity	Pain Outcomes Questionnaire‑Short Form (POQ‑SF) was assessed on the day of presentation, which was 78 out of 200 signifying moderate severity of pain. Active range of motion was restricted. Hornblower’s and external rotation tests were positive, whereas Hawkins – Kennedy and the empty can test were negative. The neurovascular examination was found to be normal.	Complete blood count (CBC) and thyroid profile labs were normal.	USG revealed a focal area of probe tenderness localized to the infraspinatus‑teres minor myotendinous junction and which appeared focal hypo‑echoic area. There was no significant subacromial-subdeltoid bursitis, glenohumeral effusion, or significant rotator cuff tear. MRI showed hyperintensity along the myotendinous junction along teres minor with focal peritendinous hyperintensity along its insertion. Focal hyperintensity was also seen along inferior fibers of the infraspinatus tendon.	The patient was started on a combination of NSAIDs and skeletal muscle relaxants 2 mg twice a day and trypsin chymotrypsin 1 mg twice a day to reduce the inflammation and swelling. Diclofenac topical solution and ice compression were applied 3–4 times a day to reduce the local tenderness for 8–10 days. After 10 days of medications, muscle strengthening exercises were started in the Physical Medicine and Rehabilitation department	Not record
18^Citation17	33	Male	Covaxin	Not record	14 days after receiving vaccination	Not record	His pain score on the visual analogue scale (VAS) was 8 out of a maximum of 10. On physical examination, his shoulder forward flexion was 0°, and he could not internally or externally rotate at the shoulder joint.	Not record	Anteroposterior X-ray revealed calcification in the supraspinatus insertion area.	He was treated by resting his upper limb in a shoulder sling and a non-steroidal anti-inflammatory drug (Naproxen 250 milligram twice daily) for 7 days.	After 1 month, he had no pain in the shoulder, and his range of shoulder motion was normal and identical to the opposite normal shoulder.
19^Citation17	53	Female	Covishield	Not record	Several hours after receiving vaccination	Not record	Evaluation of her shoulder motion using a goniometer revealed that she had mild limitation of active and passive shoulder motion (as compared to opposite normal shoulder) (forward flexion 135°, normal side 160°; external rotation with elbow adducted 60°, opposite normal 90°; internal rotation till seventh thoracic vertebra both sides. Her pain score was 8 out of a maximum of 10 on the VAS pain scale.	Not record	Magnetic resonance imaging (MRI) of her shoulder revealed the presence of subacromial and subdeltoid bursitis	NSNID treatment was ineffective. Therefore, we proceeded with a steroid injection (1 milliliter of 40 milligram triamcinolone mixed with 4 milliliter of 0.5% bupivacaine) in the subacromial space of the shoulder.	Thereafter, she reported 50% pain relief within a week and 90% pain relief within a month. A shoulder range of motion (ROM) examination revealed full ROM that was identical to the opposite normal shoulder (elevation 160°, external rotation with elbow adducted 60°and internal rotation till seventh vertebrae) after 1 month of follow-up. The patient was fully compliant with the treatment regimen.
20^Citation18	54	Male	Pfizer – BioNTech COVID-19 vaccination	Not record	Not record	Not record	The pain intensity was rated as an 8–9/10. There was also a mild-to-severe pain in the neck described as an ‘odd pain’ that throbbed, where the patient scored a 70% on the neck pain disability questionnaire. Cervical range of motion (ROM) showed a severe loss of extension mobility, a significant limitation in bilateral side bending as well as a moderate restriction in bilateral rotation. Any pressure on the head in any position exacerbated the shoulder pain particularly backwards motions. There was severe restriction on left shoulder motion above the horizontal not due to restriction but due to severe pains, there was no restriction to right shoulder motion.	Not record	Radiographic assessment was performed and analyzed using the PostureRay® EMR. The radiographs showed a very hunched neutral standing alignment. In the cervical region, the patient had a 65.7 mm forward head posture, (vs. normal <15 mm)), a flexed atlas plane line (APL: +2.6° vs. −24–29°)) and reduced cervical lordosis (−14.2° vs. −31–42° normal)). The patient also had a T2-T11 thoracic hyperkyphosis (56.0° vs. 42° normal)) and a forward lean (horizontal distance between T1 and T12) of 62.1 mm (vs. 0 mm ideal)). On the lumbar view the patient demonstrated a 71.3 mm posterior thoracic translation (vs. 0 mm normal)), a loss of lumbar lordosis (−17.2° vs. −40° normal)) and a reduced sacral base angle (SBA: 31.9° vs. 40° normal)).	Chiropractic BioPhysics (the primary purpose being to reduce the FHP and forward postural lean and thoracic hyperkyphosis). The patient progressed to performing 50 repetitions daily. Spinal manipulative therapy (SMT) was performed on the cervical, thoracic and lumbar spine bilaterally.	The patient experienced rapid pain relief with treatment, and it is noted that after 1-month of treatments (13 sessions) the patient reported ‘feeling great.’ The shoulder pain was rated a 0/10 after 33 treatments.
21^Citation19	31	Male	Not record	Second	Several hours after receiving vaccination	Not record	On injection, he noted the location of the injection site seemed unusually proximal in the deltoid, just distal to his acromion shoulder stiffness and overall pain. He did also have subacromial impingement signs with a positive Hawkins test. Both the patient’s supraspinatus empty can test, and his infraspinatus external rotation test yielded a strength score of four with notable pain in the left shoulder. These were in comparison with a painless strength score of five on the contralateral shoulder. The rest of his examination was unremarkable.	Not record	the patient received radiographs of the left shoulder, which did not show any evidence of acute trauma, superior humeral head migration, or osteoarthritis. Magnetic resonance imaging (MRI) was obtained, following clinical exclusion of other shoulder diagnoses, which showed marginal tendonitis of the supraspinatus tendon and slight edema in the subacromial area, which is nonspecific yet often associated with subacromial bursitis.	In a standard sterile fashion, the left subacromial space was injected with 20 mg triamcinolone with 9 cc of 1% Xylocaine without epinephrine.	Six days after the subacromial corticosteroid injection, the patient reported complete resolve of the pain stemming from postvaccine administration subacromial bursitis and rotator cuff tendinitis as a result of SIRVA. This included return of full active and passive shoulder range of motion, as well as painless strength scores of five in the empty can test and the external rotation test.
22^Citation20	69	Female	Sputnik V vaccine	Second	Several hours after receiving vaccination	Wrong injection site	Intense pain and loss of active (ROM). She self-rated the pain as 10 out of 10 on the visual analog scale. Physical examination revealed no visible swelling at injection site and neurovascular examination was normal. Active forward flexion was 80°, external rotation 10°, and internal rotation at the level of the sacroiliac joint. Neer and Hawkins’ tests were positive.	Not record	Plain film radiograph revealed only a mild acromioclavicular osteoarthritis, which was asymptomatic. Magnetic resonance imaging (MRI) results of the left shoulder done 5 days after the vaccination showed a mild subacromial-subdeltoid bursitis. A second MRI, done 2 months later, revealed distention of the subacromial-subdeltoid and subcoracoid bursas with associated synovial hypertrophy. After administration of intravenous contrast, intense synovial enhancement was observed.	They prescribed an intramuscular dose of depot betamethasone and a homebased program of gentle exercises.	She had a quick initial response to treatment, with a marked decrease in pain, and improvement in active ROM. However, after two months of treatment, her recovery slowed and still requires NSAIDs and physical therapy several (pondríalos meses) months of treatment, she presented no improvements in ROM and persisted with shoulder pain.

Table 2. Detailed information of subgroups. The frequency and proportion of different genders, age groups, vaccine types, injections, and causes of different diseases.

	Number	Percentage
Sex
Female	12	54.5%
Male	10	45.5%
Age
0–44	10	45.5%
45–59	8	36.4%
>60	4	18.1%
Type of Vaccine
Pfizer – BioNTech COVID-19 vaccination	8	36.4%
Covaxin	2	9.1%
Oxford/AstraZeneca COVID-19 vaccine	4	18.1%
Moderna mRNA COVID-19 vaccination	2	9.1%
Others	8	36.4%
Dose
First	7	31.8%
Second	7	31.8%
Not record	8	36.4%
Etiology
Wrong injection site	6	27.3%
Practitioners are unprofessional	2	9.1%
Inappropriate syringe selection	3	13.6%
Not record	11	50%

Results

Basic information

In this study, 19 patients were included in the analysis of SRIVA after receiving the COVID-19 vaccine. As shown in Tables 1 and 2, there was no significant difference in the proportion of males to females (12; 10). Compared to those by sex, patients who underwent SIRVA after receiving the COVID-19 vaccine were distributed into all age groups; the oldest patient was 84 years old, the youngest was 21 years old, and the mean age was 45.8 years (n = 22).

Clinical features

Most of the SIRVAs were initiates after the patients received the Pfizer – BioNTech COVID-19 vaccination (n = 8; p = 36.4%), the second was the Oxford/AstraZeneca COVID-19 vaccine (n = 4; p = 18.2%), and the relationship between dose and the morbidity of SIRVA was inconspicuous (first dose: 7; second dose: 7; not recorded: 8).The latency of SIRVA was concentrated within three days, while the longest latency was 15 days (average 4 days). However, the etiology of SIRVA patients after COVID-19 vaccine has been unclear. However, false selection of the injection site (n = 6; p = 27.3%) was the top priority, given the record of the cause of SIRVA. Additionally, unprofessional practitioner (n = 2; p = 9.1%) and inappropriate syringe selection (n = 3; p = 13.6%) were the significant causes of SIRVA according to the records.

Examinations

In terms of SRIVA symptoms, all the patients suffered from shoulder pain (n = 22 p = 100%: severe: 12 p = 54.5%; mild: 10 p = 45.5%), and the majority of patients had shoulder mobility disorders (n = 18; p = 81.8%) regardless of whether they were positive or negative. Moreover, a minority of the SIRVA patients suffered from shoulder swelling (n = 5; p = 22.7%), and fever (n = 2; p = 9.1%). In addition, some of the Neer, Hawkins, Yocum, and O’Brien test results (n = 3; p = 13.6%) were positive, indicating rotator cuff injury and synovial lesions. There was only one patient with a positive Hornblower sign (n = 1; p = 4.5%), which may indicate a greater risk of recurrent rupture of the rotator cuff ligament group in the future. As shown in Table 1, only a few patients had laboratory test records. Based on the recorded results, SIRVA patients generally exhibited an increase in inflammatory indicators such as white blood cells C-reactive protein. Few patients underwent shoulder joint puncture fluid extraction (n = 2; p = 9.1%), and result showed shoulder joint injury and suppuration. On imaging, most patients who underwent SIRVA underwent X-ray, MRI and shoulder ultrasound only when shoulder swelling was severe. The X-ray imaging findings of most SIRVA patients were nonspecific, and some patients with a longer disease course may have had calcification of the supraspinatus tendon (n = 2; p = 9.1%). MRI often revealed edema and inflammation of the shoulder (n = 12; p = 54.5%). On ultrasound, inflammatory reactions in the shoulder could often be detected (n = 4; p = 18.2%).

Treatment and outcomes

In terms of SIRVA treatment, most patients only took oral painkillers in combination, while a small number of patients underwent intra-articular injection (n = 2). Surgical indications were available for only three patients, but only two patients underwent surgical treatment; only one specific surgical procedure, shoulder joint perfusion dilation surgery, was recorded. After standardized treatment, the vast majority of patients recover. However, two patients still experienced shoulder pain and movement disorders after treatment.

Discussion

With the large-scale use of COVID-19 vaccines, cervical cancer vaccines, influenza vaccines and other vaccines, the complication rate of vaccination in the future will increase daily. The incidence rate of SIRVA increased from 2.5% in 2011 to 41.9% in 2016 according to the National Vaccine Injury Compensation Program (VICP). Therefore, it is necessary to have a solid theoretical foundation and strong technical skills to reduce the fear of vaccination recipients and decrease the incidence rate of SIRVA.

Injury mechanisms

According to our collected information, patients were mechanically injured for various reasons. Mechanistically, SIRVA involves the injection of vaccines into the synovial sac of the shoulder joint or damage to the skeletal muscles, ligaments, or even bone tissue at the injection site.⁶ The lack of professional practice by the practitioner, the incorrect choice of injection site and the improper selection of needles that we concluded ultimately led to injury of the shoulder musculoskeletal system are consistent with the results of previous studies. Additionally, consistent with our research, clinical trials in the U.S. showed that the COVID-19 mRNA vaccine, Pfizer-BioNTech vaccine and Moderna vaccine could easily cause an immune response; in other words, the immunogenicity was strong. This may be related to the protein shell and mRNA of the virus in the vaccine. Adjuvants are used routinely in vaccines, leading to enhanced immunogenicity of vaccines.² This could effectively explain why the highest incidence of SIRVA occurred after Pfizer-BioNTech vaccine injection.

Injection techniques

Immunogenicity can be achieved by providing vaccines through abundant blood vessels near the deltoid muscle and suitable adipose tissue which can be quickly identified by the immune system. Currently, five locations are used for deltoid muscle injection: A: transverse finger width 1–3 below the midpoint of the shoulder peak.²¹ B: Middle one-third of the deltoid muscle.²² C: The injection site is a triangular area, where a horizontal line is drawn 2.5–5 cm below the acromial process. The bottom of the triangle is the middle half of the horizontal line, and its vertex is inverted at the midpoint of the “arm side aligned with the armpit.”²³ D: This site is located ‘by drawing an imaginary horizontal line two to three finger breadths 2.5–5.0 cm below the lower edge of the acromion process.’ The acromion process was identified as the upper marker, the deltoid tuberosity (in line with the axilla) as the lower marker, and an imaginary triangle was drawn pointing downward from the acromion. The injection site is in the center of the triangle or the point halfway between the markers (it will be from one- to four-finger widths from the acromion, depending on the size of the arm).²⁴ E: The intersection between the anteroposterior axillary line (the line between the upper end of the anterior axillary line and the upper end of the posterior axillary line) and the line perpendicular to the mid-acromion.²⁵ A site is easy to distinguish, and is used frequently in the clinic. B site is an improvement over the A site and is more accurate than A site. C and D sites are the areas with the densest muscle tissue in the deltoid muscle, however, these sites are safer than A and B sites are, but the disadvantage is that they are difficult to identify. However, all four injection sites have been reported to cause vascular and/or nerve damage after injection.²⁶ E site was first proposed in 2017, and it was best to avoid the axillary nerve, anterior humeral artery, subacromial and deltoid bursa at this location. Research has shown that when receiving vaccination, patients should extend their arms by approximately 60 degrees and support their palms on the iliac bone, which can effectively reduce pain during injection and help medical staff grasp the injection location.²⁵ We have summarized the detailed information, advantages and disadvantages, as well as usage frequency of each injection site in Table 3. We documented that SIRVA was caused by “the incorrect injection site,” and most patients recalled “too high injection site.” This means that individuals with thinner deltoid coverage are more likely to be damaged.

Table 3. Information on commonly used injection sites for the deltoid muscle. Including its injection site, advantages and disadvantages, and frequency of use.

No.	Site	Advantage	Disadvantage	Frequency
A	1–3 transverse finger width below the midpoint of the shoulder peak.	Easy to distinguish.	Easier to harm.	Frequently
B	Middle one-third of the deltoid muscle.	Easy to distinguish.	For thin patients, it is easy to damage the surrounding soft tissues.	Often
C	The injection site is a triangular area, where a horizontal line is drawn 2.5-5 cm below the acromial process. The bottom of the triangle is the middle half of the horizontal line, and its vertex is inverted at the midpoint of the “arm side aligned with the armpit.”	The most abundant part of the deltoid muscle is conducive to drug absorption and safe relatively.	Difficult to identify.	Unusual
D	This site is located ‘by drawing an imaginary horizontal line two to three finger breadths 2.5–5.0 cm below the lower edge of the acromion process.’ Find the acromion process as the upper marker, then find the deltoid tuberosity as the lower marker, draw an imaginary triangle pointing downward from the acromion. The injection site is in the center of the triangle or the point halfway between the markers.	Safe relatively.	Difficult to identify.	Unusual
E	The intersection between the anteroposterior axillary line (the line between the upper end of the anterior axillary line and the upper end of the posterior axillary line) and the perpendicular line from the mid-acromion.	The theoretically safest injection point.	The most difficult to identify part.	Seldom

The selection of syringes should be judged based on the patient’s body shape. Long needles can lead to injection into the synovial sac and even damage the periosteum, while short needles can cause subcutaneous emphysema and ineffective vaccination. Researchers recommend the use of 16 mm needles for patients weighing 60 kilograms or less, 25 mm needles for women weighing 60–90 kilograms and for men weighing 60–118 kilograms. Patients weighing more than these weights were advised to use a 38 mm needle. In addition, some scholars believe that the selection of needles can be optimized by squeezing the skin to determine the thickness of subcutaneous tissue.²⁷ A total of three patients were categorized as inappropriate syringe selection according to our results. A 52-year-old female weighted 58 kg received injection of the vaccine via a 1-inch length (25 mm) syringe. A standard weight 52-year-old male was injected with the vaccine via a 1.5-inches syringe (38 mm). Another 55-year-old female suffered from SIRVA caused by 1 (25 mm) inch syringe selection. The incorrect needle selection in these patients was consistent with the results discussed above.Vaccination should be accomplished by medical technicians. However, nearly one-third of influenza vaccines were injected by pharmacists who were not qualified for vaccination in America. During the COVID-19 pandemic, the United States even passed bills to allow pharmacy staff and some interns to inject vaccines. The influx of large-scale nonprofessional practitioners was also a reason for the increasing incidence of vaccine related complications.⁸

Diagnosis, treatment and prognosis

The most common side effect of deltoid muscle vaccination is local redness, swelling, and pain, which can be relieved within a few days However, when the pain persists or gradually intensifies, SIRVA such as adhesive cystitis, tendonitis, or subacromial deltoid synovitis, should be considered. Imaging examination and joint cavity puncture play important roles in the diagnosis of SIRVA. At present, there is no unified diagnosis or treatment method for SIRVA internationally, but most patients can recover through oral anti-inflammatory and analgesic drugs and physical therapy. Early identification markers for SIRVA have been proposed: 1. Shoulder pain occurred <48 h after injection. 2. The patient had a duration of at least 7 days. 3. Restricted range of motion. 4. No symptoms before vaccination. Patients for whom oral medication was ineffective could choose intra-articular injection. Surgical treatment may be considered for patients with ineffective conservative treatment or secondary suppurative arthritis. Most patients have a good prognosis, but a small number of patients may experience residual shoulder pain and mild mobility disorders.²⁸

Limitations

This study has several limitations. First, all the objects were derived from case reports through December 11, 2023. Some reviews extensively reported on this case but lacked detailed information and some academic research lags, resulting in this study not including all cases. Although this study summarized the case characteristics of COVID-19-related SIRVA, analyzed the etiology of SIRVA, and tried to avoid SIRVA as much as possible, we did not propose effective new solutions. Moreover, due to the different focuses of each case series and the lack of data, this study was unable to analyze the collected results in depth.

Conclusion

SIRVA is a common complication of COVID-19 vaccine injection even any other vaccine, and has various causes. Although most patients have a good prognosis after receiving formal treatment, a small number of severe patients also require shoulder joint puncture, fluid extraction, or even surgical treatment. Therefore, it is necessary to provide training for practitioners and choose different injection points and needles for different patients. Finally, a timely diagnosis of SIRVA and an optimal treatment plan should be established. In this way, the incidence rate of SIRVA could be reduced, and the prognosis of SIRVA patients could be guaranteed.

Author contributions

LZX was the authors of the paper’s main body producers. CSJ and ZMY were the leading designer of this study and provided us with research ideas and directions.

Acknowledgments

The authors thank everyone who has contributed to this study, especially Dan Li who provided a schematic diagram for this article.

Supplemental data

Supplemental data for this article can be accessed on the publisher’s website at https://doi.org/10.1080/21645515.2024.2321672

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The raw data supporting the conclusion of this article will be made available by the authors without undue reservation.

Additional information

Funding

This study was funded by 1) the National Natural Science Foundation of China [Grant Nos. 81772866、82172594]. 2)The Wisdom Accumulation and Talent Cultivation Project of the Third Xiangyang Hospital of Central South University [YX202001, YX202212].