Seroprevalence of Antibodies to SARS-CoV-2 in US Blood Donors

  1. Ralph R. Vassallo
  2. Marjorie D. Bravo
  3. Larry J. Dumont
  4. Kelsey Hazegh
  5. Hany Kamel

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Abstract

Background

To identify blood donors eligible to donate Coronavirus Disease-2019 (COVID-19) Convalescent Plasma (CCP), a large blood center began testing for antibodies to SARS-CoV-2, the etiologic agent of COVID-19. We report the seroprevalence of total immunoglobulin directed against the S1 spike protein of SARS-CoV-2 in US blood donors.

Methods

Unique non-CCP donor sera from June 1–July 31, 2020 were tested with the Ortho VITROS Anti-SARS-CoV-2 total immunoglobulin assay (positive: signal-to-cutoff (S/C) ≥1). Donor age, sex, race/ethnicity, ABO/RhD, education, and experience were compared to June and July 2019. Multivariate regressions were conducted to identify demographics associated with the presence of antibodies and with S/C values.

Results

Unique donors (n=252,882) showed an overall seroprevalence of 1.83% in June (1.37%) and July (2.26%), with the highest prevalence in northern New Jersey (7.3%). In a subset of donors with demographic information (n=189,565), higher odds of antibody reactivity were associated with non-Hispanic Native American/Alaskan (NH-NAA/A) and Black (NH-B), and Hispanic (H) race/ethnicity, age 18-64, middle school or lesser education, blood Group A, and never or non-recent donor status. In positive donors (n=2,831), antibody signal was associated with male sex, race/ethnicity (NH-NAA/A, NH-B and H) and geographic location.

Conclusions

Seroprevalence remains low in US blood donors but varies significantly by region. Temporal trends in reactivity may be used to gauge the effectiveness of public health measures. Before generalizing these data from healthy donors to the general population however, rates must be corrected for false positive test results among low prevalence test subjects and adjusted to match the wider demography.

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  1. ScreenIT

    SciScore for 10.1101/2020.09.17.20195131: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: They are informed about antibody testing and give consent for the research use of anonymized information, blood and blood samples.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    αCoV2TIg is a chemiluminescent immunometric test qualitatively measuring total antibody (IgG, IgM and IgA) to SARS-CoV-2 S1 spike antigen.
    IgA
    suggested: None
    SARS-CoV-2 S1 spike antigen .
    suggested: None
    Software and Algorithms
    SentencesResources
    The log10-transformed S/C from donors with positive αCoV2TIg test results were regressed against seven donor demographic characteristics and blood type using general estimating equations for main effects (Proc Mixed, SAS v9.4, SAS Institute, Cary, NC).
    SAS Institute
    suggested: (Statistical Analysis System, RRID:SCR_008567)

    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 is an initial report on the first two months of screening blood donors for antibodies to SARS-CoV-2; continued reporting is necessary to define trends as public health measures are enacted and relaxed. Second, there is a lack of donor clinical information (symptomatology and laboratory confirmation of infection by PCR) and no orthogonal supplemental testing has been conducted to weed out false-positive test results in this low-prevalence population. These limit the ability to correlate antibody reactivity and S/C strength with the presence or severity of symptoms. Last, blood donors are a significantly healthier population than the general public, with substantially different demography than the general population. Generalization of data from this group of tested individuals to the population at large must be corrected for potential false positive test results and adjusted to reflect the demography of the general population before estimates of pathogen exposure are valid. Trends over time however, are valuable in the evaluation of imposition or relaxation of efforts to limit spread of the disease. While longitudinal studies are under way to better characterize pathogen exposure, data like ours also provide a rapid estimate of regional differences in the number of infected individuals as we progress through substantial morbidity and mortality toward herd immunity.10 As commonly seen in the setting of traumatic events, blood donor...

    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.

  2. Version published to 10.1101/2020.09.17.20195131v1 on medRxiv