key: cord-0710013-lhnzvjq7 authors: Xu, Ru; Huang, Jieting; Duan, Chaohui; Liao, Qiao; Shan, Zhengang; Wang, Min; Rong, Xia; Li, Chengyao; Fu, Yongshui; Wang, Hao title: Low prevalence of antibodies against SARS‐CoV‐2 among voluntary blood donors in Guangzhou, China date: 2020-08-19 journal: J Med Virol DOI: 10.1002/jmv.26445 sha: 1bdaf630d085dbf60e2d2cd742279a5bb2952c13 doc_id: 710013 cord_uid: lhnzvjq7 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. Coronavirus disease 2019 (COVID- 19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The most commonly reported clinical symptoms include fever, cough and fatigue. Other symptoms such as nasal congestion, rhinorrhea, sore throat, muscle pain and diarrhea are less common 1 . While the majority of cases result in mild symptoms, some progress to viral pneumonia and multi-organ failure 2 . SARS-CoV-2 is an enveloped virus in the genus of beta-coronavirus, but it is significantly different from SARS-CoV and MERS-CoV 3, 4 . Until today there has been no solid evidence indicating that such respiratory viruses can be transmitted by blood transfusion 5, 6 . However, considering the incubation period of SARS-CoV-2 infections (median 5.2 days) and the fact that some can be asymptomatic, blood safety remains a general concern 7-10 . Currently, the diagnosis of COVID-19 mainly relies on the laboratory detection of SARS-CoV-2 RNA in throat swab samples and clinical diagnosis is supported by pulmonary computed tomography 11 . The positive rate of SARS-CoV-2 RNA found in blood samples of clinical confirmed patients is still relatively low (15-20%) 1, 12 . A recent study recruited blood donors (BDs) in Wuhan city of China between January 25 and March 4, 2020. The results showed 4 out of 2,430 BDs (0.16%) to be positive for SARS-CoV-2 RNA 13 . This was during the peak of the SARS-CoV-2 outbreak in Wuhan, with approximately 50,000 confirmed cases. Although the blood products This article is protected by copyright. All rights reserved. have not been transfused to clinical patients, the possibility of transfusion-associated SARS-CoV-2 transmission in areas with an intense epidemic cannot be excluded. The first COVID-19 case in Guangzhou, a city of south China, was diagnosed on January 22, 2020. A total of 499 cases had been confirmed by April 17. In order to study the status of SARS-CoV-2 infection among BDs in Guangzhou and evaluate the risk of transfusion transmission, we conducted tests on the antibodies against the virus supported by epidemiological evaluation. Preliminary studies indicated that antibody testing was suitable for serosurvey of blood samples of individuals who had been exposed to SARS-CoV-2 14 . In this study, after total antibodies screening, three different antibody Ig subtypes (IgM, IgA, and IgG) and viral nucleic acid were assessed to indicate past and active COVID-19 infection. The study participants consisted of 2,199 voluntary blood donors, who were randomly selected from March 23 through April 2, 2020. Among them, 1,489 were male and 710 were female. The median of age was 34 years old (ranging from 18 to 59 years old). Before donation, the BDs were required to meet the defined criteria of whole blood and platelet apheresis donation. During the COVID-19 outbreak, BDs were required to answer an additional questionnaire on whether in the past 28 days they 1) had close contact with confirmed or suspected cases of COVID-19; 2) had traveled in areas with active COVID-19 epidemic; 3) had such symptoms as fever, cough, fatigue, sore throat, muscle pain or diarrhea. This article is protected by copyright. All rights reserved. In addition, the BDs were tested for body temperature. For BDs who were positive for SARS-CoV-2 nucleic acid or antibody testing, an epidemiological survey was conducted, and their family members and close contacts were given the same tests. For each participant, 10 ml of whole blood sample was drawn for the tests. Informed consent was obtained and the study was approved by the Ethics Committee of Guangzhou Blood Center. 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