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Volume 27, Number 2—February 2021
Research Letter

Long-Term Humoral Immune Response in Persons with Asymptomatic or Mild SARS-CoV-2 Infection, Vietnam

Huynh Kim MaiComments to Author , Nguyen Bao Trieu, Trinh Hoang Long, Hoang Tien Thanh, Nguyen Dinh Luong, Le Xuan Huy, Lam Anh Nguyet, Dinh Nguyen Huy Man, Danielle E. Anderson, Tran Tan Thanh, Nguyen Van Vinh Chau, Guy Thwaites, Lin-Fa Wang, Le Van TanComments to Author , and Do Thai Hung
Author affiliations: Pasteur Institute, Nha Trang City, Vietnam (H.K. Mai, N.B. Trieu, T.H. Long, H.T. Thanh, N.D. Luong, L.X. Huy, D.T. Hung); Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam (L.A. Nguyet, T.T. Thanh, G. Thwaites, L.V. Tan); Hospital for Tropical Diseases, Ho Chi Minh City (D.N.H. Man, N.V.V. Chau); Duke-NUS Medical School, Singapore (D.E. Anderson, L.-F. Wang); Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK (G. Thwaites); SingHealth Duke-NUS Global Health Institute, Singapore (L.-F. Wang)

Main Article

Figure

Antibody responses in 11 study participants, weeks 1–20 after PCR diagnosis of SARS-CoV-2 infection, Vietnam, 2020. A) Seroprevalence of SARS-CoV-2 among 11 COVID-19 patients. We followed testing protocols and the positive cutoff of 20% recommended in the Elecsys Anti–SARS-CoV-2 assay (Roche, https://diagnostics.roche.com) without any modification. Using these parameters, previous studies showed an excellent concordance between results from surrogate virus neutralization tests and conventional neutralizing antibody detection assays (3,4). Vertical bars denote 95% CIs. Graphs were created using GraphPad Prism version 8.0 (GraphPad software, https://www.graphpad.com). B) Kinetics of neutralizing antibodies measured by the surrogate neutralization assay (GenScript, https://www.genscript.com) with the 20% cutoff applied. We tested samples at 1:10 dilution as specified. Because of the limited availability of plasma samples, each sample was tested only once. RBD, receptor-binding domain; NAbs, neutralizing monoclonal antibodies; S, spike; N, nucleocapsid.

Figure. Antibody responses in 11 study participants, weeks 1–20 after PCR diagnosis of SARS-CoV-2 infection, Vietnam, 2020. A) Seroprevalence of SARS-CoV-2 among 11 COVID-19 patients. We followed testing protocols and the positive cutoff of 20% recommended in the Elecsys Anti–SARS-CoV-2 assay (Roche, https://diagnostics.roche.com) without any modification. Using these parameters, previous studies showed an excellent concordance between results from surrogate virus neutralization tests and conventional neutralizing antibody detection assays (3,4). Vertical bars denote 95% CIs. Graphs were created using GraphPad Prism version 8.0 (GraphPad software, https://www.graphpad.com). B) Kinetics of neutralizing antibodies measured by the surrogate neutralization assay (GenScript, https://www.genscript.com) with the 20% cutoff applied. We tested samples at 1:10 dilution as specified. Because of the limited availability of plasma samples, each sample was tested only once. RBD, receptor-binding domain; NAbs, neutralizing monoclonal antibodies; S, spike; N, nucleocapsid.

Main Article

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Page updated: January 24, 2021
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