SARS-CoV-2 Seroprevalence Survey Estimates Are Affected by Anti-Nucleocapsid Antibody Decline

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Abstract

We analyzed 21 676 residual specimens from Ontario, Canada collected March–August 2020 to investigate the effect of antibody decline on SARS-CoV-2 seroprevalence estimates. Testing specimens orthogonally using Abbott (anti-nucleocapsid) and Ortho (anti-spike) assays, seroprevalence estimates were 0.4%–1.4%, despite ongoing disease activity. The geometric mean concentration (GMC) of antibody-positive specimens decreased over time (P = .015), and GMC of antibody-negative specimens increased over time (P = .0018). Association between the 2 tests decreased each month (P < .001), suggesting anti-nucleocapsid antibody decline. Lowering Abbott antibody index cutoff from 1.4 to 0.7 resulted in a 16% increase in positive specimens.

Article activity feed

  1. Roger Dodd

    Review 2: "SARS-CoV-2 seroprevalence survey estimates are affected by anti-nucleocapsid antibody decline"

    This study cautiously asserts that the outcome of a seroprevalence study is impacted by the declining prevalence rate, which impacts the sensitivity. Reviewers suggest the conclusion is rational and largely justifiable but limited by the data they utilize.

  2. Samreen Zaidi

    Review 1: "SARS-CoV-2 seroprevalence survey estimates are affected by anti-nucleocapsid antibody decline"

    This study cautiously asserts that the outcome of a seroprevalence study is impacted by the declining prevalence rate, which impacts the sensitivity. Reviewers suggest the conclusion is rational and largely justifiable but limited by the data they utilize.

  3. SciScore for 10.1101/2020.09.28.20200915: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Ethics: Ethics approval for the serosurveys was granted by the PHO Ethics Review Board
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Laboratory testing: Using an orthogonal testing approach, we first tested specimens with the Abbott Architect SARS-CoV-2 IgG test (Abbott Laboratories, USA), which detects anti-nucleocapsid (N) antibodies, then tested positive samples with the Ortho-Clinical Diagnostics VITROS Anti-SARS-CoV-2 IgG test (Ortho-Clinical Diagnostics, Inc., USA), which detects anti-spike (S) antibodies [8].
    anti-nucleocapsid (N)
    suggested: None
    Anti-SARS-CoV-2 IgG
    suggested: None
    anti-spike (S)
    suggested: None
    Specimens that were positive using both tests were considered positive for SARS-CoV-2 antibodies.
    SARS-CoV-2
    suggested: None
    Software and Algorithms
    SentencesResources
    Laboratory testing: Using an orthogonal testing approach, we first tested specimens with the Abbott Architect SARS-CoV-2 IgG test (Abbott Laboratories, USA), which detects anti-nucleocapsid (N) antibodies, then tested positive samples with the Ortho-Clinical Diagnostics VITROS Anti-SARS-CoV-2 IgG test (Ortho-Clinical Diagnostics, Inc., USA), which detects anti-spike (S) antibodies [8].
    Abbott Architect
    suggested: (Abbott ARCHITECT i1000sr System, RRID:SCR_019328)
    Abbott Laboratories
    suggested: None
    To explore the effect of lowering the Abbott index value on population seroprevalence, we analyzed a subset of specimens with an index value of 0.7, otherwise maintaining the same orthogonal approach as above.
    Abbott
    suggested: (Abbott, RRID:SCR_010477)

    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: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    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.