Early Viral Clearance and Antibody Kinetics of COVID-19 Among Asymptomatic Carriers

  1. Tongyang Xiao
  2. Yanrong Wang
  3. Jing Yuan
  4. Haocheng Ye
  5. Lanlan Wei
  6. Xuejiao Liao
  7. Haiyan Wang
  8. Shen Qian
  9. Zhaoqin Wang
  10. Lei Liu
  11. Zheng Zhang

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Abstract

Asymptomatic carriers contribute to the spread of Coronavirus Disease 2019 (COVID-19), but their clinical characteristics, viral kinetics, and antibody responses remain unclear. A total of 56 COVID-19 patients without symptoms at admission and 19 age-matched symptomatic patients were enrolled. RNA of SARS-CoV-2 was tested using transcriptase quantitative PCR, and the total antibodies (Ab), IgG, IgA, and IgM against the SARS-CoV-2 were tested using Chemiluminescence Microparticle Immuno Assay. Among 56 patients without symptoms at admission, 33 cases displayed symptoms and 23 remained asymptomatic throughout the follow-up period. 43.8% of the asymptomatic carriers were children and none of the asymptomatic cases had recognizable changes in C-reactive protein or interleukin-6, except one 64-year-old patient. The initial threshold cycle value of nasopharyngeal SARS-CoV-2 in asymptomatic carriers was similar to that in pre-symptomatic and symptomatic patients, but the positive viral nucleic acid detection period of asymptomatic carriers (9.63 days) was shorter than pre-symptomatic patients (13.6 days). There were no obvious differences in the seropositive conversion rate of total Ab, IgG, and IgA among the three groups, though the rates of IgM varied largely. The average peak IgG and IgM COI of asymptomatic cases was 3.5 and 0.8, respectively, which is also lower than those in symptomatic patients with peaked IgG and IgM COI of 4.5 and 2.4 ( p < 0.05). Young COVID-19 patients seem to be asymptomatic cases with early clearance of SARS-CoV-2 and low levels of IgM generation but high total Ab, IgG, and IgA. Our findings provide empirical information for viral clearance and antibody kinetics of asymptomatic COVID-19 patients.

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  1. Version published to 10.3389/fmed.2021.595773
  2. ScreenIT

    SciScore for 10.1101/2020.04.28.20083139: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: This study was approved by the Ethics Committee of Shenzhen Third People’s Hospital (2020-169), which waived the requirement for written patient consent for this retrospective analysis.
    Consent: All patients gave their oral consent to participate in this study.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The SARS-CoV-2 specific total antibody (Ab), IgG, IgA, and IgM in plasma was tested using a Chemiluminescence Microparticle Immuno Assay (CMIA).
    IgG
    suggested: None
    IgA
    suggested: None
    IgM in plasma
    suggested: None
    Software and Algorithms
    SentencesResources
    All statistical analysis was performed using GraphPad Prism 8.3.0 (
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    (GraphPad Software, La Jolla, California, USA, www.graphpad.com).
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    This study has several limitations. First, this study was a single-center retrospective study, and multiple-center clinical observations are needed to evaluate the clinical, viral, and immunological characteristics of asymptomatic carriers with SARS-CoV-2 infection. Second, possible selection bias of enrolled patients may be present. As The Third People’s Hospital of Shenzhen is the only government mandated facility for the treatment of COVID-19, the study is generally representative of those infected with the disease. Third, it is unclear whether low levels of IgM play a protective role in asymptomatic carriers. Additional insights are needed which could strengthen the existing control measures in China. In this study, asymptomatic carriers were found to be younger, with a lower initial viral load, early viral clearance,mild laboratory changes, mild chest CT manifestations, undetectable IgM and moderate levels of IgG. This sheds light on the management and potential immune mechanisms of viral clearance in asymptomatic carriers, useful tools that are needed to improve and strengthen existing care guidelines.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.04.28.20083139v1 on medRxiv