Journal of the American Pharmacists Associatio n japha.org 102 JAPhA | 53:2 | MAR/APR 2013 VACCINE UPDATE Erroneous administration of intramuscular vaccines, particu- larly above the deltoid muscle, can result in serious shoulder injuries and diminished vaccine efficacy. 1 With few studies published ad- dressing injection technique before 2002, inconsistencies arose regard- ing optimal vaccine administration, thus causing variations in current practice. 2 We will examine cases of serious shoulder injuries as a result of incorrect technique and provide a step-by-step guide to the proper administration of intramuscular in- jections. In 2006, Bodor and Montalvo 3 reported two cases of vaccine-re- lated shoulder dysfunction. One patient received the 23-valent pneu- mococcal vaccine and the other an influenza vaccine. Both patients re- ported receiving injections high into the deltoid muscle, within 1 to 2 cm of the acromion. Both patients no- ticed severe shoulder pain and loss of range of motion within 2 days and increasing pain during a period of 2 to 5 months. One patient was diag- nosed with subacromial bursitis that later progressed to adhesive capsuli- tis or frozen shoulder; the other was diagnosed with bicipital tendonitis, subacromial bursitis, and a mild C6 sensory radiculopathy. The authors recommended that guidelines spec- ify avoiding vaccine injections in the upper third of the deltoid muscle. They recommended that health pro- fessionals consider vaccine-related shoulder dysfunction in patients presenting with shoulder pain and weakness following a vaccine injec- tion. Atanasoff et al. 4 reported a series of 13 cases submitted to the Vaccine Injury Compensation Program be- tween 2006 and 2010, in which pa- tients experienced shoulder injury related to vaccine administration. Of the cases, 62% received influenza vaccine and the remainder received tetanus–diphtheria toxoids, Td– acellular pertussis, or human papil- lomavirus vaccine. The proposed mechanism of injury was that vac- cine, an antigenic substance, injected into synovial tissue resulted in an immune-mediated inflammatory re- sponse. Of patients, 46% stated that the vaccine was injected “too high” into the deltoid muscle. Magnetic resonance images revealed fluid col- lections in the deep deltoid or over- lying the rotator cuff tendons, bur- sitis, fluid buildup within the bursa, or rotator cuff tears. About one-third of patients (31%) required surgery, with one-half of those requiring a Vaccine administration: Preventing serious shoulder injuries Stephan Foster and McLisa V. Davis second surgical intervention. Many patients (69%) had residual symp- toms, and 31% experienced full re- covery. The authors proposed seat- ing both the injector and the patient to reduce the probability of injecting high into the deltoid muscle. Injecting into the thickest, most central portion of the deltoid muscle is important in preventing these se- vere shoulder injuries. The injection must be administered into the mus- cle at a 90-degree angle to the skin. Health professionals need to remain knowledgeable about the anatomy of the shoulder (Figure 1) to avoid injecting too high. Further, review- ing current recommendations for in- tramuscular injections helps ensure that proper technique is used. Recommendations for intra- muscular vaccine administration are as follows 5–7 : Humerus Deltoid muscle Acromion Clavicle Articular capsule Subacromial bursa Supraspinatus muscle and tendon Synovial membrane Figure 1. Cross-section of the shoulder joint Send your immunization questions to the JAPhA Contributing Editors who coor- dinate the Vaccine Update column: ❚ Mary S. Hayney, PharmD, BCPS, Associate Professor of Pharmacy, School of Pharmacy, University of Wisconsin, Madison (mshayney@pharmacy. wisc.edu) ❚ John D. Grabenstein, PhD, Director of Scientific Affairs, Merck Vaccine Division (john_gra- [email protected]) This article is supported by a Cooperative Agreement provided by the Centers for Disease Control and Prevention (CDC) entitled “Pharmacists: Connecting, Communicating and Collaborating for Improved Community Health” (1U66 IP000114). The opinions expressed in this article do not represent the viewpoints of the CDC.