Vasovagal reactions in whole blood and apheresis donors: a cross-sectional study on donor haemovigilance data from 2016 to 2019 in Italy.

BACKGROUND: Acute and delayed vasovagal reactions (VVR) are the most frequent adverse reactions (AR) associated with donations. The aim of this study was to provide the data of the Italian donor haemovigilance system and contextualise the VVR data within the international framework, as well as evaluating, among first-time donors, the association of gender and age and the prevalence of VVR compared to other AR. MATERIALS AND METHODS: The prevalence analysis was performed on VVR and other AR notified to the Italian haemovigilance system from 2016 to 2019. The analysis on the association of gender and age group and VVR prevalence was performed on first-time donations. The definitions and severity of AR were as set out in the 2014 ISBT/IHN international standards. RESULTS: From 2016 to 2019, 34,519 AR were notified, of which 87.1% were VVR. The overall VVR prevalence was 25.0/10,000 donations and the overall prevalence of other AR was 3.7/10,000 donations. All the estimated prevalences of AR were higher for first-time donations than for regular donations and lower for whole blood than for apheresis donations. No difference was noted between whole blood and apheresis donations for VVR with complications or injuries. The prevalence of AR among first-time donors was higher in females than in males. The prevalence of VVR decreased as donor age increased. DISCUSSION: The prevalence of VVR related to blood donation was very low and similar to those calculated by other haemovigilance systems. Among first-time donors, the prevalence of AR was higher in females than in males. The higher prevalence of VVR in young donors and a significant decreasing trend by age group confirmed the results reported in the literature. Finally, no trend by age group in first-time donors was observed for other AR to donations.