Antibody kinetics and serologic profiles of SARS-CoV-2 infection using two serologic assays

• Published in: PloS one Vol. 15; no. 10; p. e0240395
• Main Authors: Kweon, Oh Joo, Lim, Yong Kwan, Kim, Hye Ryoun, Kim, Min-Chul, Choi, Seong-Ho, Chung, Jin-Won, Lee, Mi-Kyung
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 22-10-2020; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Aged, 80 and over; Antibodies; Antibodies, Viral - blood; Antibodies, Viral - immunology; Antigens; Betacoronavirus - immunology; Biology and life sciences; Coronavirus Infections - immunology; Coronavirus Infections - virology; Coronaviruses; COVID-19; Diagnosis; Diagnostic systems; Enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - methods; Enzymes; Epidemiology; Epitopes; Female; Fluorescent Antibody Technique - methods; Follow-Up Studies; Humans; Immunoassay; Immunoassays; Immunoglobulin G; Immunoglobulin G - blood; Immunoglobulin G - immunology; Immunoglobulin M; Immunoglobulin M - blood; Immunoglobulin M - immunology; Infections; Infectious diseases; Internal medicine; Kinetics; Laboratories; Male; Medical diagnosis; Medical schools; Medicine; Medicine and Health Sciences; Middle Aged; Pandemics; Patients; Pneumonia, Viral - immunology; Pneumonia, Viral - virology; Research and Analysis Methods; Respiratory diseases; SARS-CoV-2; Sensitivity and Specificity; Serologic Tests - methods; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Testing; Viral diseases; Young Adult; South Korea
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0240395

Coronavirus disease 2019 (COVID-19) is an emerging threat worldwide. This study aims to assess the serologic profiles and time kinetics of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with COVID-19 using two immunoassays.
A total of 97 samples serially collected from 17 patients with COVID-19 and 137 negative control samples were analyzed for IgM and IgG against SARS-CoV-2 using the AFIAS COVID-19 Ab (Boditech Med Inc., Chuncheon, Republic of Korea) and the EDI™ Novel Coronavirus COVID-19 ELISA Kit (Epitope Diagnostics, Inc., San Diego, CA).
With both assays, IgM and IgG rapidly increased after 7 days post symptom onset (PSO). IgM antibody levels reached a peak at 15-35 d PSO and gradually decreased. IgG levels gradually increased and remained at similar levels after 22-35 d. The diagnostic sensitivities of IgM/IgG for ≤14d PSO were 21.4%/35.7~57.1% and increased to 41.2~52.9%/88.2~94.1% at >14 d PSO with specificities of 98.5%/94.2% for AFIAS COVID-19 Ab and 100.0%/96.4% for EDI™ Novel Coronavirus COVID-19 ELISA Kit. Among 137 negative controls, 12 samples (8.8%) showed positive or indeterminate results.
The antibody kinetics against SARS-CoV-2 are similar to common findings of acute viral infectious diseases. Antibody testing is useful for ruling out SARS-CoV-2 infection after 14 d PSO, detecting past infection, and epidemiologic surveys.