RESUMO
BACKGROUND AND OBJECTIVES: Vasovagal reactions (VVR) are the most common adverse reactions in blood donation. This study aimed to provide and analyze the data of the regional hemovigilance system in Chongqing, China from 2020 to 2022, report the prevalence and explore the risk factors of VVR. MATERIALS AND METHODS: R software (version 4.2.3) was used for all statistical analyses. Frequency and composition rates were used to describe the data of total donation, as well as data on the different types of ADR. The Chi-square test was used to analyze risk factors for VVR and inter-group comparisons of VVR stratified by gender (female/male), age (18-22; 23-29; 30-39; 40-49; 50-60) and season(Spring (Mar.-May.); Summer (Jun.-Aug.); Autumn (sep.-Nov.); Winter (Dec.-Feb.)). RESULTS: The reported incidence rate of VVR was 8.69 during whole blood donations and 1.02 during platelet-apheresis donations.The stratified analysis revealed that female donors aged 18-22 years old and 30-39 years old were reported to have lower VVR rates than male donors, oppositely, higher in females in 50-60 years old. Statistically significant differences in the incidence rate of VVR were observed between winter and summer, and between winter and spring in 18-49 years old. No seasonal variation was found in 50-60 years old. CONCLUSIONS: The reported incidence rate of VVR related to blood donation was very low and varied from those calculated by other haemovigilance systems. The higher prevalence of VVR in young, first-time donors, college students, donating in mobile vehicles, males and in spring. Among first-time donors, the prevalence of VVR was higher in males than in females; and stratified analysis revealed there were seasonal variation and gender differences within a same age group.