key: cord-0073262-qm831ck0
authors: Wang, Shichun; Song, Min; Liu, Qi; Yao, Chunyan
title: SARS-CoV-2 seroprevalence among blood donors, Chongqing, China, January 1 to May 31, 2020
date: 2022-01-10
journal: J Formos Med Assoc
DOI: 10.1016/j.jfma.2022.01.004
sha: b962edc29e510bf29e97ef76c3337d1977902b85
doc_id: 73262
cord_uid: qm831ck0

nan

Correspondence SARS-CoV-2 seroprevalence among blood donors, Chongqing, China, January 1 to May 31, 2020

To the editor, Coronavirus disease 2019 (COVID-19) is a highly contagious respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. 1 Several asymptomatic COVID-19 cases that were more in the endemic areas where coronaviruses have arisen are being reported. 2 Like the Middle East respiratory syndrome (MERS) and the 2003 severe acute respiratory syndrome (SARS) viruses, SARS-CoV-2 viral RNA can be detected in the blood. Therefore, asymptomatic cases pose a great potential risk for the safety of the blood supply.

There are only a few studies on blood transfusion screening for the SARS-CoV-2 virus, which suggested that there was a low detection rate of SARS-CoV-2 RNA in plasma or serum for blood donors (Supplementary Table 1 ). Besides, considering that nasopharyngeal swabbing is a uncomfortable procedure and improper sample collection is known to contribute to false-negative results, 3 nucleic acid test may not be suitable for SARS-CoV-2 infection screening in blood stations. Based on the kinetic characteristics of SARS-CoV-2 specific antibodies response, 4 we tested plasma samples from 498 blood donors after donation between January 1 and May 31, 2020 for the presence of IgM/IgG antibodies to SARS-CoV-2 (Novel coronavirus (SARS-CoV-2) IgM antibody detection kits (G202003004, G202003001, G202005001, G202004005) and IgG antibody detection kits (G202003307, G202003002, G202004311, G202004004) were purchased from Bioscience Diagnostic Technology Co. Ltd., Chongqing, China.). Demographic characteristics of the blood donors were seen in Supplementary Table 2 . To understand the level of exposure to the virus in different cohorts, we surveyed 248 blood donors who were medical personnel (Supplementary Figure 1) and 250 donors from the general population. Also, to assess the risk of infection due to lifting the Wuhan lockdown, 250 blood donors of the general population were selected randomly from January 1 to May 31, 2020 (Fig. 1) . Plasma samples from all the blood donors tested negative for SARS-CoV-2 IgM/IgG antibodies. Regardless of whether the donations were done before, during, or after the Wuhan lockdown, the relative light units (RLU) of all samples from the blood donors was less than the cut-off (CO) value, which meant that the S(sample RLU)/CO ratio was less than 1.0. Therefore, all plasma samples were considered to have tested negative for SARS-CoV-2 IgM/IgG antibodies. The risk for transfusion transmission of SARS-CoV-2 seems to be negligible. Among these 498 donors, 25 donated blood repeatedly from January 1 to May 31 in 2020, and all of them were apheresis component donors, with an average of 4.08 donations per donor, up to 9 donations. In addition, as a retrospective study, there were no reports of COVID-19 infection among blood donors enrolled in this study, nor any reports of COVID-19 infection in the patients who accepted these blood components beyond 14 days after the sample collection.

In conclusion, this is the first SARS-CoV-2 and seroprevalence survey among blood donors in China. Our results show that there is no evidence of widespread SARS-CoV-2 transmission in Chongqing, a 32 million population directadministrated municipality in geographical proximity to Hubei province where Wuhan is located, after the successful containment of Wuhan outbreak in early 2020. This finding does not support the argument that humanity must learn to coexist with COVID-19 because SARS-CoV-2 has already spread everywhere through asymptomatic transmission. 

Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China

Coronavirus disease 2019: coronaviruses and blood safety

Diagnostic performance of different sampling approaches for SARS-CoV-2 RT-PCR testing: a systematic review and meta-analysis

Seroprevalence of immunoglobulin M and G antibodies against SARS-CoV-2 in China

Chongqing Blood Bank of the People's Liberation Army, Chongqing, 400038, China Chunyan Yao* Department of Blood Transfusion, First Affiliated Hospital

The authors are very grateful to Ronghua Diao and Shan Wang for their help in collecting samples. We would like to thank Editage (www.editage.cn) for English language editing.

Supplementary data to this article can be found online at https://doi.org/10.1016/j.jfma.2022.01.004.