Right after my shingles shot a few months ago, I had deltoid area redness, pain, and inflammation for four days. Symptoms were generalized to the entire shoulder area making it difficult to even use my arm.

My primary care doctor had warned me beforehand about this being a Shingrix effect. But after reading an article in a healthcare publication, it seems possible that perhaps some of these side effects could have to do with techniques used by injectors.

And as nations around the world start vaccinating citizens against COVID-19, the instructions from pharmaceutical expert Lu-Ann Murdoch (which I’m posting below) should be read and heeded by all those who will be doing the injecting, to potentially minimize the risks of shoulder injuries after COVID-19 shots.

The vaccines will be delivered into the same deltoid area as many others. According to Pfizer study results published in the New England Journal of Medicine, a good proportion of those who get vaccinated can expect some soreness for a few days.

Appropriate injection techniques are imperative. Canadian health providers who will be doing vaccinations, starting today, have received instruction. With permission from Canadian HealthcareNetwork.ca, here’s some more information about deltoid injections from Murdoch.

For citations, health professionals can consult the original article.

By Lu-Ann Murdoch

Shoulder injury is an infrequent occurrence after vaccine administration, but all immunizers must be aware of and be able to recognize this adverse event and refer patients for appropriate treatment when needed.

It’s also important for immunizers to periodically review proper intramuscular injection technique to minimize the occurrence of a post-vaccination shoulder injury.

Many vaccines typically cause transient (24- to 48-hour) soreness at the injection site. However, shoulder injury related to vaccine administration (SIRVA) is typified by persistent shoulder pain with restriction of motion and function that can persist for months if not treated.(1) Patients usually have no history of shoulder dysfunction, but experience a rapid onset of pain, usually starting within 48 hours of vaccine administration, and limited range of motion, which do not improve with over-the-counter analgesics.

Several cases of shoulder injury related to vaccine administration have been reported in the literature. Many of the cases have been in women who received influenza vaccine at a pharmacy or doctor’s office.(4-6) The problem results from injecting the vaccine too high into the shoulder, into or too close to underlying nonmuscular tissues.(1,4,5) The resulting inflammation in the musculoskeletal structures of the shoulder (e.g., bursae, tendons, and ligaments) results in shoulder pain and a limited range of motion.

If a patient complains of shoulder pain or inability to lift their arm, ask if they received a vaccine injection in that arm recently. If they answer in the affirmative, suspect shoulder injury related to vaccine administration and refer the patient to a physician for a diagnosis.(1) Diagnostic imaging (e.g., ultrasound), nonsteroidal anti-inflammatory drugs, corticosteroid injections into the shoulder, and physiotherapy may be required.(

Although shoulder injury related to vaccine administration is caused by injection administered too high in the shoulder, other structures near the deltoid muscle can also be injured when a vaccine is administered improperly. For example, injections below the deltoid can hit the radial nerve, while those too far to the side of the deltoid can hit the axillary nerve. In these situations, patients often experience immediate, strong shooting and burning pain and may later develop paralysis or neuropathy that doesn’t always resolve.(1)

Needle length selection is also important. A needle that’s too long may pass through the deltoid muscle and hit the bone, which can reduce vaccine absorption and immunity. A needle that’s too short can result in subcutaneous administration, which can also lead to reduced immunity, as well as nodules, cellulitis, or localized lipoatrophy.

To reduce the risk of shoulder and nerve injuries associated with vaccination, immunizers should review appropriate injection technique and anatomical ‘landmarks’ when administering intramuscular vaccines. Several helpful tips are provided below:

  • Determine the patient’s weight to select the proper needle length. Choose a 5/8-inch needle for smaller patients (< 60 kg) and a 1-inch needle for patients who weigh 60–70 kg. Use either a 1-inch or 1.5-inch needle for women weighing 70–90 kg or men weighing 70–118 kg. Use a 1.5-inch needle for women weighing > 90 kg and men weighing > 118 kg.
  • Sit or kneel when injecting a seated patient. Injection too high into the shoulder may be more likely if the immunizer is standing while the patient is sitting.
  • When a shirt can’t be removed to expose the shoulder, roll the sleeve up. Don’t pull the shirt’s neck over the shoulder.
  • Ensure that the injection is given in the thick, centrally located portion of the deltoid muscle, away from the upper third of the deltoid where the risk of over-penetration into underlying structures of the shoulder is greatest. To do this, review the proper landmarking technique for the deltoid muscle. Measure two to three finger-widths below the acromion process to ensure you inject below the shoulder capsule. Identify the level of the armpit as your lower level. See the infographic available at https://www.cfp.ca/content/cfp/65/1/40.full.pdf.
  • After determining the upper and lower limits, make a V-shape with your thumb and forefinger to outline the deltoid and keep the ‘sweet spot’ visible before picking up the needle.
  • Give the injection at a 90° angle using a darting motion.

All immunizers can play a key role in preventing shoulder and nerve injuries associated with vaccination by always use landmarking to establish the correct injection area. Even the most experienced healthcare professionals need to review proper injection technique and sharpen their skills periodically.

Originally appeared on the online home of the Medical Post, CanadianHealthcareNetwork.ca, a website only accessible to healthcare professionals.