The Prevalence of Antibodies to SARS-CoV-2 Among Blood Donors in China

BACKGROUND: The prevalence of antibodies to SARS-CoV-2 among blood donors in China remains unknown. To reveal the missing information, we investigated the seroprevalence of SARS-CoV-2 antibodies among blood donors in the cities of Wuhan, Shenzhen and Shijiazhuang of China. STUDY DESIGN AND METHODS: During January to April 2020, 42,794 samples from 38,144 healthy blood donors in the three cities were tested for total antibody (TAb) against SARS-CoV-2. Pseudotype SARS-CoV-2 neutralization tests (ppNAT) were further performed for all TAb-positive samples to confirm the antibody presence. The IgG against viral nucleocapsid protein (IgG-N) and receptor-binding domain (RBD) of the spike protein (IgG-RBD), and IgM against RBD antigen were also evaluated. Risk factors associating with SARS-CoV-2 seropositivity were analyzed. RESULTS: A total of 519 samples from 410 donors were confirmed by neutralization tests. The SARS-CoV-2 seroprevalence among blood donors was 2·29% (407/17,794, 95%CI: 2·08%-2·52%) in Wuhan, 0·029% (2/6,810, 0·0081%-0·11% in Shenzhen, and 0·0074% (1/13,540, 95%CI: 0·0013%-0·042%) in Shijiazhuang, respectively. The earliest emergence of SARS-CoV-2 seropositivity in blood donors was identified on January 20, 2020 in Wuhan. The weekly prevalence of SARS-CoV-2 antibodies in Wuhan’s blood donors changed dynamically, and were 0·08% (95%CI: 0·02%-0·28%) during January 15-22 (before city lockdown), 3·08% (95%CI: 2·67%-3·55%) during January 23 to April 7 (city quarantine period) and 2·33% (95%CI: 2·06%-2·63%) during April 8-30 (after lockdown easing). Female and older-age were identified to be independent risk factors for SARS-CoV-2 seropositivity among donors in Wuhan. CONCLUSION: The prevalence of antibodies to SARS-CoV-2 among blood donors in China was low, even in Wuhan city. According to our data, the earliest emergence of SARS-CoV-2 in Wuhan’s donors should not earlier than January, 2020. As most of population of China remained uninfected during the early wave of COVID-19 pandemic, effective public health measures are still certainly required to block viral spread before a vaccine is widely available.FUNDING STATEMENT: None. The research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.DECLARATION OF INTERESTS: The authors declare no competing interests. ETHICS APPROVAL STATEMENT: This study was reviewed and approved by the Medical Ethical Committee of Beijing Hospital (2020BJYYEC‐070‐01) and written informed consent was obtained from each enrolled donor before donation.