Risk of bursitis and other injuries and dysfunctions of the shoulder following vaccinations.

While vaccination injection site adverse reactions are usually mild and transient in nature, several cases of bursitis and other shoulder injuries have been reported in the medical literature. However, these lesions are not included in vaccine label inserts. To identify the characteristics of post-vaccination shoulder injuries and those of patients and involved vaccines, as well as their potential causes, a systematic review of the cases of vaccination-related bursitis and other shoulder injuries reported in the literature and notified to the Spanish Pharmacovigilance System database (FEDRA) have been conducted. We found 45 cases of bursitis and other shoulder injuries that appeared following the vaccine intramuscular injection given into the deltoid muscle (37 from the systematic review of the literature, and 8 from the scrutiny in the Spanish Pharmacovigilance System database, FEDRA). All the patients were adult, 71.1% females, with a mean and median age of 53.6years (range: 22-89). The most frequently involved vaccines were influenza and pneumococcal vaccines, respectively; followed by diphtheria-tetanus-pertussis, diphtheria-tetanus toxoid, human papillomavirus, and hepatitis A vaccines. The most frequent shoulder lesion was bursitis. Most of patients required medical care due to severe local pain and arm mobility restriction. In a majority of cases, symptoms started 48h post vaccination. Subdeltoid or subacromial bursitis and other shoulder lesions may be more common than suspected. Such lesions predominantly affect women. The cause may be related to antigens or adjuvants contained in the vaccines that would trigger an immune or inflammatory response. However, they are more likely to be the consequence of a poor injection technique (site, angle, needle size, and failure to take into account patient's characteristics, i. e., sex, body weight, and physical constitution). Therefore, vaccination-related shoulder injuries would be amenable to prevention.