Abstract
Background Timely diagnosis of SARS-CoV-2 infection is a prerequisite for treatment and prevention. The serology characteristics and complement diagnosis value of the antibody test to RNA test need to be demonstrated.
Method Serial sera of 80 patients with PCR-confirmed COVID-19 were collected at the First Affiliated Hospital of Zhejiang University, China. Total antibody (Ab), IgM and IgG antibodies against SARS-CoV-2 were detected, and the antibody dynamics during the infection were described.
Results The seroconversion rates for Ab, IgM and IgG were 98.8%, 93.8% and 93.8%, respectively. The first detectible serology marker was Ab, followed by IgM and IgG, with a median seroconversion time of 15, 18 and 20 days post exposure (d.p.e) or 9, 10 and 12 days post onset (d.p.o), respectively. The antibody levels increased rapidly beginning at 6 d.p.o. and were accompanied by a decline in viral load. For patients in the early stage of illness (0–7 d.p.o), Ab showed the highest sensitivity (64.1%) compared to IgM and IgG (33.3% for both, p<0.001). The sensitivities of Ab, IgM and IgG increased to 100%, 96.7% and 93.3% 2 weeks later, respectively. When the same antibody type was detected, no significant difference was observed between enzyme-linked immunosorbent assays and other forms of immunoassays.
Conclusions A typical acute antibody response is induced during SARS-CoV-2 infection. Serology testing provides an important complement to RNA testing in the later stages of illness for pathogenic specific diagnosis and helpful information to evaluate the adapted immunity status of patients.
Abstract
Antibody responses were induced after SARS-CoV-2 infection, and the complementary diagnostic value of antibody test to RNA test was observed. Antibody tests are critical tools in clinical management and control of SARS-CoV-2 infection and COVID-19.
Footnotes
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Data availability: We will share individual participant data that underlie the results reported in this article after deidentification (text, tables, figures and appendices). The data will be available beginning 6 months after the major findings from the final analysis of the study were published, ending 2 years later. The data will be shared with investigators whose proposed use of the data has been approved by an independent review committee identified for individual participant data meta-analysis. Proposals should be directed to chenyuzy@zju.edu.cn. To gain access, data requestors will need to sign a data access agreement.
Support statement: This study was funded by the China National Mega-Projects for Infectious Diseases (2017ZX10103008) and the Science and Technology Major Project of Xiamen (3502Z2020YJ01). The funders had no role in the study design, data collection, data analysis, data interpretation, or writing of the report. No support was received from any organisation for the submitted work except language editing by Springer Nature Author Service. China National Mega-Projects for Infectious Diseases; Grant: 2017ZX10103008; the Science and Technology Major Project of Xiamen; Grant: 3502Z2020YJ01.
Conflict of interest: Mrs Lou has nothing to disclose.
Conflict of interest: Dr. Li has nothing to disclose.
Conflict of interest: Dr. Zheng has nothing to disclose.
Conflict of interest: Dr. Su has nothing to disclose.
Conflict of interest: Dr. Li has nothing to disclose.
Conflict of interest: Mr. Liu has nothing to disclose.
Conflict of interest: Dr. Yu has nothing to disclose.
Conflict of interest: Prof. Ge has nothing to disclose.
Conflict of interest: Dr. Zou has nothing to disclose.
Conflict of interest: Dr. Yuan has nothing to disclose.
Conflict of interest: Dr. Lin has nothing to disclose.
Conflict of interest: Mr. Hong has nothing to disclose.
Conflict of interest: Dr. Yao has nothing to disclose.
Conflict of interest: Mr. Zhang has nothing to disclose.
Conflict of interest: Dr. Wu has nothing to disclose.
Conflict of interest: Mr. Zhou has nothing to disclose.
Conflict of interest: Dr. Hou has nothing to disclose.
Conflict of interest: Dr. Li has nothing to disclose.
Conflict of interest: Dr. Zhang has nothing to disclose.
Conflict of interest: Dr. Zhang has nothing to disclose.
Conflict of interest: Dr. Fan has nothing to disclose.
Conflict of interest: Prof. Zhang has nothing to disclose.
Conflict of interest: Prof. Xia has nothing to disclose.
Conflict of interest: Dr. Chen has nothing to disclose.
- Received March 19, 2020.
- Accepted May 8, 2020.
- Copyright ©ERS 2020
This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.
