PERFORMANCE AND UTILITY OF AN ORAL FLUID-BASED RAPID POINT-OF-CARE TEST FOR SARS-COV-2 ANTIBODY RESPONSE FOLLOWING COVID-19 INFECTION OR VACCINATION

  1. Paturi V. Rao
  2. Dhanalakshmi Nair-Shaef
  3. Siting Chen
  4. Steven C. Kazmierczak
  5. Charles T. Roberts
  6. Srinivasa R. Nagalla

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Abstract

Analysis of anti-SARS-CoV-2 antibodies can identify recent-onset or prior COVID-19 infection or vaccine-induced humoral immunity. We have developed a rapid point-of-care test for IgG, M, or A-class immunoglobulins that recognize the S1 domain of the SARS-CoV-2 spike protein (CovAb™). The test employs a lateral-flow strip design with a recombinant SARS-CoV-2 spike protein S1 domain capture antigen to detect anti-SARS-CoV-2 antibodies in oral fluid samples. Oral fluid samples are collected with a swab that captures the gingival crevicular fluid component of oral fluid that represents a plasma transudate and that is the primary source of oral fluid monomeric antibodies. The sensitivity of the CovAb™ test is 97.29% and the specificity is 98.13%, and the results obtained are similar to those obtained using matched fingerstick whole blood samples and in an EUA-approved commercial serology test. Oral fluid SARS-CoV-2 antibodies could be detected in subjects more than 7 months post-symptom onset. We also demonstrate the utility of the CovAb™ test in characterizing adaptive immune responses to vaccination in COVID-19-naïve and exposed populations after first and second vaccine doses and show that significant heterogeneity in magnitude of antibody titers achieved is seen after both doses and that prior COVID-19 exposure increases the adaptive immune response to vaccination.

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  1. ScreenIT

    SciScore for 10.1101/2021.06.28.21259657: (What is this?)

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

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variableAs shown in Table 9, the rate of positive responses in all three groups was greater for females that males (77 vs 62%, 78 vs 53%, and 96 vs 82%, respectively, in the COVID-19-naïve dose 1, COVID-exposed dose 1, and COVID-19-naïve dose 2 groups.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Recombinant SARS-Cov-2 spike protein S1 domain produced in human embryonic kidney HEK293 cells (Diabetomics, Inc.) and goat anti-human IgG, IgA, and IgM (Jackson ImmunoResearch Laboratories, Inc.) were used for capture and detection of SARS-CoV-2 antibodies.
    anti-human IgG, IgA, and IgM
    suggested: None
    We also determined the persistence of oral fluid antibodies in the antibody-positive subjects.
    antibody-positive subjects.
    suggested: None
    As shown in Table 4, the CovAb™ test detected antibodies up to 7.2 months post-symptom onset in >8% of the antibody-positive group.
    antibody-positive group.
    suggested: None
    Comparator EUA serology test (Siemens total antibody test): Fingerstick whole-blood samples were obtained from 38 subjects who tested positive with the CovAb™ test using GCF, and all were also positive in the CovAb™ test using these whole blood samples.
    GCF
    suggested: None
    Of this group, 32 (37%) were antibody-negative and 51 (63%) were antibody-positive, a proportion similar to the COVID-19-naïve group.
    antibody-positive
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Recombinant SARS-Cov-2 spike protein S1 domain produced in human embryonic kidney HEK293 cells (Diabetomics, Inc.) and goat anti-human IgG, IgA, and IgM (Jackson ImmunoResearch Laboratories, Inc.) were used for capture and detection of SARS-CoV-2 antibodies.
    HEK293
    suggested: CLS Cat# 300192/p777_HEK293, RRID:CVCL_0045)

    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.

    Results from scite Reference Check: We found no unreliable references.

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  2. Version published to 10.1101/2021.06.28.21259657v1 on medRxiv