Vaccine administration during COVID-19 pandemic: an overview of safe injection technique and local complications

Opening Vignette Madam Tan, a 65-year-old housewife, visited your clinic for left shoulder pain. The pain started 1 day after she was vaccinated in her left shoulder at a vaccination drive. Your initial assessment was that of postinjection site pain. You prescribed her with a course of nonsteroidal anti-inflammatory drugs (NSAIDs) and advised rest. She returned a week later with worsening and severe pain over her left shoulder, which affected her daily activities. Clinical examination showed generalised tenderness and effusion over her left shoulder joint with limited range of motion. Madam Tan recollected that she felt the injection had been given ‘too high and too deep’. Due to the temporal nature of the symptoms, you suspected that her shoulder pain could be related to vaccine administration. Due to the progressing severity of the symptoms, you referred her to a tertiary hospital for orthopaedic evaluation.HOW RELEVANT IS THIS TO MY PRACTICE? Vaccination is a procedure routinely performed by doctors and nurses in the primary healthcare setting. In the adult population, the most common site for vaccination is the deltoid muscle. The deltoid muscle is preferred due to its size and ease of exposure and administration on a seated patient in the clinic setting. The vaccine needs to be administered with the proper technique to maximise its efficacy and minimise the risk of an adverse event at the injection site. During the coronavirus disease 2019 (COVID-19) pandemic, large-scale vaccination programmes were held, and a potential rise in complications from vaccinations is expected. Therefore, it is important to have in place safe and competent vaccination practices. WHAT TO EXPECT AT THE INJECTION SITE? Common symptoms postinjection include induration, erythema and pain at the injection side. These symptoms are usually self-limiting and resolve spontaneously over a week. More serious complications, such as shoulder injury related to vaccine administration (SIRVA), are rare. There is a spectrum of shoulder pathologies contributed by poor injection techniques. It includes traumatic injury or inappropriate administration of vaccine material into the subdeltoid bursa or shoulder joint, leading to an inflammatory cascade and damage to the surrounding structures. The first local case of SIRVA complication following COVID-19 vaccination was reported in 2021.[1] WHAT CAN I DO IN MY PRACTICE? It is important that the family physician or nursing practitioner perform safe vaccination for each patient. To achieve this, good working knowledge of the following is necessary: (a) shoulder anatomy and surface landmarking; (b) appropriate needle selection; (c) safe injection technique; (d) alternate injection site; and (e) approach to postvaccination injection site and shoulder pain. It is recommended to counsel the patient about common local site reactions, such as induration, pain and erythema, and red flags suggestive of more serious complications. Shoulder anatomy and surface landmarking The deltoid is a large triangular-shaped muscle overlying the glenohumeral joint. The muscle originates from the lateral third of the clavicle, acromion and scapula spine, and it inserts into the deltoid tuberosity of the humerus. There are several potential structures that can be injured in deltoid injections [Figure 1]. The needle should aim to deposit the vaccine into the muscle bulk of the deltoid without injury to the surrounding structures. The deltoid muscle lies beneath the skin and a layer of subcutaneous fat. When the patient has a significantly thick subcutaneous layer, a short needle might result in vaccine deposition limited to this layer and causes unwanted cutaneous reactions such as subcutaneous nodules, sterile abscesses, lipoatrophy and subcutaneous emphysema.[2] The subacromial bursa extends distal to the lateral border of the acromion by 3–6 cm, while the subdeltoid bursa lies beneath the deltoid muscle bulk.[3] When the needle is directed ‘too high’ or ‘too deep’, inappropriate injection into these communicating bursae results in bursitis. The two nerves at risk of injury include the radial nerve and the anterior branch of the axillary nerve. Radial nerve injury has been reported when the injection is too posterior, damaging the nerve as it passes obliquely around the proximal humerus to enter the spiral groove.[2] When the injection is too proximal and deep, it can cause an injury to the anterior branch of the axillary nerve as it winds round the surgical neck of the humerus. A deep injection, where the needle contacts the proximal humerus, can result in bone contusion and osteonecrosis.Figure 1: Illustration of shoulder anatomy shows structures that can be injured during a deltoid injection. Care must be taken to identify the correct entry point and to select an appropriately sized needle to achieve optimal tissue penetration (lowest needle). The top needle demonstrates inappropriately administered injection that is ‘too high’ and ‘too deep’ with resultant penetration into the subdeltoid bursa. The middle needle demonstrates inappropriately administered injection with underpenetration, resulting in subcutaneous deposition of vaccine.The risk of damage to the surrounding structures is mitigated with proper patient position and surface landmarks. The arm and shoulder of the patient need to be exposed adequately for proper visualisation and palpation of key landmarks. It is not advisable to pull down a loose collar or roll up a tight sleeve to expose the shoulder, as the appropriate landmarks cannot otherwise be accurately identified. The healthcare provider should be seated for accurate assessment of the surface landmarks and proper administration of the vaccine. The patient should also be seated to prevent injury in the event of vasovagal syncope following vaccination. Appropriate needle selection The needle length determines the depth of vaccine deposition and is selected according to the body habitus and weight of the patient.[4] The absorption and efficacy of the vaccine are compromised when it is not deposited in the deltoid muscle bulk. A short needle might result in subcutaneous deposition and lead to cutaneous reactions.[2] A long needle might result in penetration into the subdeltoid bursa or shoulder joint, or impact against the head of humerus, which can potentially lead to SIRVA.[2] Recent studies have recommended 16-mm needles for patients weighing less than 60 kg, 25-mm needles for females weighing between 60 and 90 kg and males weighing between 60 and 118 kg, and 38-mm needles for both genders beyond these weight groups.[2,4] Safe injection technique There are several techniques described for identifying the injection site. These include: (a) measured distance from the lateral acromion by two to three finger breaths (approximately 4 cm); (b) midpoint of an inverted triangle with its base two or three finger breaths below the lateral border of the acromion and its apex on a line drawn laterally from the anterior axilla fold onto the deltoid; (c) midpoint between the lateral border of the acromion and deltoid tuberosity; and (d) middle third of deltoid. Studies have shown that even with the abovementioned techniques, there are still risks of injury to the surrounding structures.[2] Cook et al.[2] proposed the following technique in which the vaccinated arm is abducted to 60° with hand placed on the ipsilateral hip, and the injection is at the midpoint between the lateral border of the acromion and deltoid tuberosity. This relaxes the deltoid muscle, allowing a less-painful injection, improves visualisation of the deltoid tuberosity, avoids the subacromial bursa and moves the axillary nerve proximally.[2,5] The following framework is our recommendation for the safe administration of intramuscular deltoid vaccination. A pictorial illustration is presented in Figure 2.Figure 2: Clinical photographs show the recommended vaccination technique from the (a) front view and (b) vaccinator’s point of view. The vaccinator and the patient are seated. The patient is seated with arm held abducted with hand on ipsilateral hip. (a) The lateral border of the acromion and deltoid tuberosity are identified by palpation. (b) An imaginary line is drawn between the lateral border of the acromion to deltoid tuberosity. The vaccine is subsequently administered at the midpoint of these two landmarks (cross in a & b) into the deltoid muscle bulk, with the needle perpendicular to the skin. Both the vaccine administrator and the recipient are seated at the same level. There is adequate exposure of shoulder to visualise and palpate the surface landmarks. The recipient’s arm is abducted at 60° with his/her hand placed on the ipsilateral hip. Surface landmarking: the vaccinator places his/her hand on the deltoid with the index finger on the acromion and the thumb on the deltoid tuberosity. The injection is directed at the midpoint of a line between the two digits [Figure 2b]. The needle gauge is selected according to the habitus of the patient. The needle is directed perpendicular to the skin surface for accurate assessment of the depth of its penetration. Select an alternative injection site (e.g., vastus lateralis in the anterolateral thigh) if there are contraindications, such as poor skin conditions (e.g., extensive scars, active infection) or significant history of shoulder injury or surgery. If there is evidence of infection around the proposed injection site, the vaccine is best given at an alternate area. Alternate injection site The vastus lateralis muscle found in the lateral thigh can be used as an alternative injection site. This is a commonly used injection site in infants and toddlers due to its larger muscle bulk compared to the deltoid muscle in this age group. Similar to deltoid injections, the injected area (thigh and leg) should be adequately exposed. The injection site is along the middle third of a line between the greater trochanter and the lateral femoral condyle, laterally situated on the thigh. The injection should also be given at an angle of 90° to the skin.[6] Approach to postvaccination complications Injection site pain and tenderness is a common complaint after vaccination, but it is typically mild and self-limiting.[1,7] Commonly reported vaccination site-localised symptoms include muscle pain, erythema or induration of the skin, and they do not typically affect the range of motion or function of the shoulder.[8] A more serious complication is SIRVA, which typically presents with symptoms such as severe shoulder pain, weakness and decreased range of motion of the shoulder joint, which can persist for months after vaccination.[7–9] The physical examination findings of SIRVA are similar to those of other routine shoulder injuries, with the hallmark feature being that the symptoms and signs typically develop within 48 h following vaccination and do not improve with regular analgesics.[4] Routine radiographs have a limited role in the diagnosis of SIRVA, but are useful to exclude other pathologies.[10] Magnetic resonance imaging (MRI) is useful for evaluation of a suspected case of SIRVA. Typical findings observed on MRI of patients with SIRVA include subacromial bursitis, joint synovitis, adhesive capsulitis and rotator cuff injury.[1,11] There is no consensus on the optimal treatment of SIRVA. The current mainstay of treatment includes nonsteroidal anti-inflammatory drugs, physiotherapy and intra-articular corticosteroid injections.[3] Surgery might be indicated for cases refractory to conservative management.[12] There are only modest improvements reported for patients with SIRVA treated with either conservative or surgical measures.[13] Only a quarter to a third of patients achieve full recovery and a significant number of patients have residual symptom.[7,10] WHEN SHOULD I REFER TO A SPECIALIST? The primary care provider plays a critical role in our local vaccination programme and is often the first responder when a patient returns with a complication. Red flag symptoms include severe shoulder pain, limited range of motion and weakness occurring after vaccination, often persisting despite rest and analgesia. Such presentations warrant a specialist referral for further work-up and managements. TAKE HOME MESSAGES Intramuscular deltoid vaccination is a common procedure in the primary care setting, and we need to take the necessary steps to ensure safe and efficacious vaccinations. The steps for safe intramuscular deltoid vaccination include proper patient positioning, exposure of injection site, appropriate needle selection, identification of surface landmarks and safe injection technique. It is important to educate patients on local reactions postvaccination and red flag symptoms. A patient suspected of SIRVA should be referred to a specialist for further evaluation. Closing Vignette An orthopaedic surgeon reviewed Madam Tan and an MRI of her left shoulder showed extensive subacromial bursitis and rotator cuff tendonitis with joint effusion. In view of the temporal nature of her symptoms (started 48 h after intramuscular deltoid injection) and MRI findings, she was diagnosed with SIRVA. She was treated conservatively with analgesia (including NSAIDs) and physiotherapy. She was able to perform her daily activities after a year of recovery.Financial support and sponsorship Nil. Conflicts of interest How CH is a member of the SMJ Editorial Board. SMC CATEGORY 3B CME PROGRAMME Online Quiz: https://www.sma.org.sg/cme-programme Deadline for submission: 07 December 2023