Number and rate of vasovagal reactions (VVRs) stratified by donation number. The solid bars represent the number of VVRs that occurred on each donation number. The dashed line represents the rate of VVRs expressed by donation number for all donors; for example, the rate of VVRs on the first donation recorded for all donors in the registry was 0.6% for whole blood and 2.1% for apheresis plasma donations. The majority of VVRs occurred during the first two donations in the whole blood group and during the first three donations in the apheresis plasma group. No VVR occurred after donation number five in the whole blood group, whereas 33 VVRs occurred during donation numbers six and twenty-one in the apheresis plasma group.