What three years of COVID-19 vaccine administration reveals about the incidence of shoulder injury related to vaccine administration (SIRVA).

Background
Shoulder injury related to vaccine administration (SIRVA) has been reported to be a rare but real complication of vaccination. It is considered attributable to an incorrect vaccine administration technique by the vaccinator. To date, evidence about SIRVA is mainly limited to case studies and case series, and the incidence remains unknown. This study aimed to determine the incidence of SIRVA.
Methods
We conducted a retrospective study of the publicly available Eudravigilance database (pharmacovigilance data). We examined all COVID-19 vaccine case reports administered between January 2020 and December 2022. Reports were analysed to see if they met the Surveillance of Adverse Events Following Vaccination In the Community (SAEFVIC) definition and inclusion criteria for SIRVA. Data was extracted.
Findings
Between January 2020, and December 2022, from 1,172,583,008 administered COVID-19 vaccines, 43,192 cases met the SAEFVIC inclusion criteria for SIRVA. This equals an incidence of 3·7 cases per 100,000 vaccines administered during the three years. Female subjects are disproportionately affected, with 33,828 cases (77.9 %). The incidence was higher with some COVID-19 vaccine formulations than others.
Interpretation
The incidence found in this study is higher than previously reported. The data also reflects that it affects more female subjects than males. While previously considered avoidable using the correct vaccine administration technique, the data challenges this notion as it shows that certain vaccine formulations may be associated with a higher incidence of the condition. The causes of SIRVA are likely multifaceted, with current understanding being further impacted by unclear definitions and reporting requirements.