ABSTRACT
【Objective】 To investigate the risk factors of vasovagal reactions(VVR) related to plasma donation, so as to put forward clinical suggestions for early identification and accurate intervention of high-risk groups to ensure the safety of plasma donation. 【Methods】 The demographic characteristics(i.e. gender, age, weight) and records of plasma donors(donation history, pulse before plasma donation, duration of collection, etc.) were collected from July to December 2019 in a region of Sichuan. Based on logistic regression analysis, the correlation between these factors and the risk of VVR was explored. 【Results】 The information of 69 172 donors was collected, and the incidence of VVR was 7.04‰. The risk of VVR was reduced by 99% in the group with plasma collection duration less than 30 minutes compared with the group with plasma collection duration more than 50 minutes(OR, 0.01; 95% CI, 0.00~0.01; P<0.001). The risk of male group was 94 % lower than that of female group(OR, 0.06; 95% CI, 0.04~0.10; P<0.001). Compared with the 45~50 kg group, the risk of weight greater than 80 kg group decreased by 80%(OR, 0.20; 95% CI, 0.09~0.42; P<0.001). The risk of repeated donation group was 34 % lower than that of the first time donation group(OR, 0.66; 95% CI, 0.47~0.91; P<0.001). The risk of VVR in the group with pulse greater than 90 bpm before plasma donation was 2.43 times that in the 60~69 bmp group(OR, 2.43; 95% CI, 1.75~3.36; P<0.001). 【Conclusion】 Duration of plasma collection, gender, weight, frequency of plasma donation, pulse before plasma donation and donor status are independent risk factors for plasma donation-related VVR. Among them, plasma collection duration, gender and weight were the main independent risk factors for plasma donation-related VVR. For donors with plasma collection duration more than 50 minutes, female and low weight, higher risk of VVR was presented and more preventive intervention should be given.
ABSTRACT
To investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.
