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J Med Virol ; 93(3): 1743-1747, 2021 03.
Article in English | MEDLINE | ID: covidwho-1196459


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 the respiratory system, whether it is present in the bloodstream and whether it poses a threat to the blood supply during the period of the outbreak is of serious public concern. In this study, we used enzyme-linked immunosorbent assay (ELISA) to screen total antibodies against SARS-CoV-2 in 2199 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 polymerase chain reaction. Among the 2199 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 out of 2199 (0.09%) of samples were positive for IgG and IgA. There would be a limited necessity for the implementation of such testing in blood screening in a COVID-19 low-risk area.

Antibodies, Viral/blood , Blood Donors/statistics & numerical data , COVID-19/epidemiology , SARS-CoV-2/immunology , Adolescent , Adult , China , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , RNA, Viral/blood , Young Adult
Zhongguo Bingdubing Zazhi = Chinese Journal of Viral Diseases ; - (6):445, 2020.
Article in English | ProQuest Central | ID: covidwho-1126081


Objective To establish an index system for comprehensive evaluation of public health risks of the coronavirus diseases 2019(COVID-19),and to evaluate the COVID-19 in different counties(districts) of Wenzhou, so as to provide scientific evidence for the implementation of targeted prevention and control measures. Methods Rank-sum ratio(RSR) was used to evaluate 12 quality indicators of 5 categories by brain storming method with data including the incidence of COVID-19 and public health risks of COVID-19 epidemic in Wenzhou during January and February, 2020.The regional public health risks of COVID-19 were ranked according to rank-sum ratio size. Results The top three counties(districts) with most reported cases were Yueqing,Rui′an and Lucheng,accounting for 61.90%(312/504) of the total number in Wenzhou.The ratio of import cases to indigenous cases was 1∶1.39.The top three counties(districts) reported most clustering epidemics were Yueqing,Rui′an and Lucheng,accounting for 62.03%(49/79) of the total number in Wenzhou.About 70.63%(356/504)of the cases were found before the medical visit.The time from onset to first medical visit was 2.39 d, and the time from medical visit to diagnosis was 4.49 d.The average number of close contacts for confirmed cases was 29,and the top three counties(districts)with most reported average number of close contacts were Jingkai(135 cases),Dongtou(59 cases)and Cangnan(50 cases).Among all13 counties(districts),Longgang,Wencheng and Jingkai were at lower level,Yueqing and Lucheng were at higher level,and the other counties(districts)were at the middle level of public health risks of COVID-19. Conclusions RSR method is flexible and simple.It has no specific requirements on samples,and can eliminate the effects of comprehensive assessment indexes of different dimension.It has high value in evaluating public health risks of the COVID-19.The evaluating of public health risks of COVID-19 should be strengthened.Targeted prevention and control measures should be taken to positively prevent the outbreak of COVID-19.

iScience ; 24(3): 102187, 2021 Mar 19.
Article in English | MEDLINE | ID: covidwho-1093067


Dysregulated immune cell responses have been linked to the severity of coronavirus disease 2019 (COVID-19), but the specific viral factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were currently unknown. Herein, we reveal that the Immunoglobulin-like fold ectodomain of the viral protein SARS-CoV-2 ORF7a interacts with high efficiency to CD14+ monocytes in human peripheral blood, compared to pathogenic protein SARS-CoV ORF7a. The crystal structure of SARS-CoV-2 ORF7a at 2.2 Å resolution reveals three remarkable changes on the amphipathic side of the four-stranded ß-sheet, implying a potential functional interface of the viral protein. Importantly, SARS-CoV-2 ORF7a coincubation with CD14+ monocytes ex vivo triggered a decrease in HLA-DR/DP/DQ expression levels and upregulated significant production of proinflammatory cytokines, including IL-6, IL-1ß, IL-8, and TNF-α. Our work demonstrates that SARS-CoV-2 ORF7a is an immunomodulating factor for immune cell binding and triggers dramatic inflammatory responses, providing promising therapeutic drug targets for pandemic COVID-19.