SARS-CoV-2 IgG antibody responses in rt-PCR-positive cases: first report from India

  1. Girish Chandra Dash
  2. Debaprasad Parai
  3. Hari Ram Choudhary
  4. Annalisha Peter
  5. Usha Kiran Rout
  6. Rashmi Ranjan Nanda
  7. Jaya Singh Kshatri
  8. Srikanta Kanungo
  9. Subrata Kumar Palo
  10. Nityananda Mandal
  11. Sanghamitra Pati
  12. Debdutta Bhattacharya

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

Introduction. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses remain poorly understood and the clinical utility of serological testing is still unclear.

Aim. To understand the relationship between the antibody response to SARS-CoV-2 infection and the demographics and cycle threshold ( C t ) values of confirmed RT-PCR patients.

Methodology. A total of 384 serum samples were collected from individuals between 4–6 weeks after confirmed SARS-CoV-2 infection and tested for the development of immunoglobulin class G (IgG) against SARS-CoV-2. The C t values, age, gender and symptoms of the patients were correlated with the development of antibodies.

Results. IgG positivity was found to be 80.2 % (95 % CI, 76.2–84.2). Positivity increased with a decrease in the C t value, with the highest (87.6 %) positivity observed in individuals with C t values <20. The mean (± sd ) C t values for IgG positives and negatives were 23.34 (±6.09) and 26.72 (±7.031), respectively. No significant difference was found for demographic characteristics such as age and sex and symptoms and antibody response. The current study is the first of its kind wherein we have assessed the correlation of the RT-PCR C t with the development of IgG against SARS-CoV-2.

Conclusion. Although C t values might not have any relation with the development of symptoms, they are associated with the antibody response among SARS-CoV-2-infected individuals.

Article activity feed

  1. Version published to 10.1099/acmi.0.000267 on Access Microbiology
  2. ScreenIT

    SciScore for 10.1101/2020.11.13.20229716: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Testing for SARS-CoV-2 IgG: Semi-quantitative SARS-CoV-2 IgG testing was performed using ARCHITECT i2000SR platform which uses chemiluminescent microparticle immunoassay (CMIA) technology for the detection of immunoglobulin class G (IgG) antibodies against the nucleocapsid protein of SARS-CoV-2 from human serum.
    SARS-CoV-2 IgG
    suggested: None
    immunoglobulin class G (IgG
    suggested: None
    Software and Algorithms
    SentencesResources
    Data analysis: Data were entered using MS- Excel and descriptive statistical analysis were performed using SPSS software (IBM SPSS statistics for Windows, version 24.0, Armonk, NY).
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    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:
    The predominant positive male population over female could be a limitation of the current study to depict the original IgG prevalence in different gender. There was also no statistically significant association between ct value and the development of symptoms. One of the earlier study found that antibody titre cannot be corelated with SARS-CoV-2 disease severity which can be corroborated by this data also.12 Without the use of a standard curve using reference materials, the ct value by itself cannot be interpreted directly as viral load13, however ct can be used as a indicative of viral load in an infected individual. There are additional implications from our study for blood banks wherein donors are screened for antibodies using qualitative antibody tests for convalescent plasma to treat Covid-19 patients. To support a previous diagnosis of SARS-CoV-2, these facilities often relied on self-reporting about patient history and onset of symptoms. The correlation of ct values with a semi-quantitative SARS-CoV-2 IgG assay can provide significant assistance in plasma donor selection. The current study is the first of its kind wherein we have assessed the correlation of ct of RT- PCR with the development of IgG against SARS-CoV-2. Ct value might not have any relation with the severity of the diseases but is associated with the antibody response by the SARS- CoV-2 infected persons. However further long-term studies of longitudinal follow-up of a cohort will help in better understand...

    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 10.1101/2020.11.13.20229716 on medRxiv