Teres minor injury related to vaccine administration

Shoulder injury related to vaccine administration is a relatively rare disorder, which occurs as a result of vaccine being inadvertently injected into the subdeltoid/subacromial bursa, rotator cuff, and or underlying bone. We present 2 cases of shoulder injury related to vaccine administration in 2 women of ages 38 and 42 with injury to the teres minor tendon insertions on magnetic resonance imaging, a location not previously described. When faced with a patient with chronic shoulder pain following a vaccination, the possibility of vaccine deposition or injury to the teres minor tendon insertion should be considered.