This literature report (initial receipt 04-Dec-2012) concerns a 22 year old female patient with a weight of 120 lbs (54 kg) and no significant prior medical history. The patient had previously been exposed to influenza vaccine. Signs of adhesive capsulitis and rotator cuff tear with cortical irregularity 6 months after a routine seasonal flu injection were the symptoms of shoulder injury related to vaccine administration. The patient presented with acute left shoulder pain, which limited her range of motion and functional ability. The patient as in her usually state of health until she received the influenza vaccine (batch unspecified) approximately 2 months before initial presentation. The 2011 seasonal flu vaccine was given by a trained medical technician, who reported placing the vaccine '3 fingers from the acromion' (measured at 2.75 inches or approximately 7 cm) in the middle of the deltoid, 'hubbing' (inserting the needle to the depth of the plastic hub but not depressing surrounding skin) a 1-inch, 23-gauge needle, and injecting the vaccine. The patient reported having the onset of shoulder pain at the administration pain at the administration site within 2 hours of vaccination. Over the next 6 weeks, she progressive limitations of her range of motion of her left shoulder and increasing pain, 9 out of 10 pain on a pain scale. On examination, the patient had very limited range of motion and experienced pain with both active and passive range of motion. Plain radiographs were unremarkable. Ultrasound imaging, at 9.5 weeks after the initial injection, demonstrated a partial tear of the supraspinatus tendon as well as cortical irregularity on the superolateral humeral head at the point of injection. MRI (magnetic resonance imaging), at 8 weeks after the initial injection, showed joint effusion in the subacromial bursa, a longitudinal partial tear of the supraspinatus tendon, and a consistent bony contusion. Due to her limited range of motion, the patient had an immediate referral to sports medicine and was referred for aggressive physical therapy. At 11 weeks after initial presentation, the patient was re-evaluated and found to have significant improvement in pain (1 out of 10) at rest, reporting discomfort with use of the left shoulder but no limitations in function. Ultrasound images at that time demonstrated residual fluid at the supraspinatus with a consistent cortical irregularity. In follow up with the patient, at 16 months after the initial injection, she reports that her range of motion and strength continue to allow her to conduct all her desired daily activities. Reporter's comments: Her reaction was reported to the Vaccine Adverse Event Reporting System as a case of shoulder injury related to vaccine administration, likely due to injection of the influenza vaccine into the subacromial bursa. This case serves as a catalyst for discussion regarding vaccination technique and the potential to prevent complications arising from vaccine over penetration. The patient in this case, at a weight of 120 lbs (54 kg), would have had a 1/2-inch needle length, half the size of the needle recommended. These methods could potentially prevent SIRVA (shoulder injury related to vaccine administration) as well as other problems associated with overpenetration of vaccination.