Low prevalence of antibodies against SARS‐CoV‐2 among voluntary blood donors in Guangzhou, China

Xu, Ru; Huang, Jieting; Duan, Chaohui; Liao, Qiao; Shan, Zhengang; Wang, Min; Rong, Xia; Li, Chengyao; Fu, Yongshui; Wang, Hao

Since the first case of COVID‐19 reported in late December of 2019 in Wuhan, China, the SARS‐CoV‐2 virus has caused approximately 20 million infections and 732 thousand deaths around the world by 11 August, 2020. Although the pathogen generally infects respiratory system, whether it is present in the bloodstream and whether it poses a threat to the blood supply during the period of outbreak is a serious public concern. In this study, we used ELISA to screen total antibodies against SARS‐CoV‐2 in 2,199 blood donors who had donated blood at the Guangzhou Blood Center during the epidemic. The Ig‐reactive samples were further characterized for IgA, IgG and IgM subtypes by ELISA and viral nucleic acid by real‐time PCR. Among the 2,199 plasma samples, seven were reactive under total antibodies screening. Further testing revealed that none of them had detectable viral nucleic acid or IgM antibody, but two samples contained IgA and IgG. The IgG antibody titers of both positive samples were 1:16 and 1:4, respectively. Our results indicated a low prevalence of past SARS‐CoV‐2 infection in our blood donors, as none of the tests were positive for viral nucleic acid and only 2/2,199 (0.09%) of samples were positive for IgG and IgA. There would be limited necessity of implementation of such testing in blood screening in COVID‐19 low‐risk area. This article is protected by copyright. All rights reserved.