Antibody reactivity against SARS-CoV-2 in adults from the Vancouver metropolitan area, Canada

  1. Abdelilah Majdoubi
  2. Sarah E. O’Connell
  3. Christina Michalski
  4. Sarah Dada
  5. Sandeep Narpala
  6. Jean Gelinas
  7. Disha Mehta
  8. Claire Cheung
  9. Manjula Basappa
  10. Matthias Görges
  11. Vilte E Barakauskas
  12. David M. Goldfarb
  13. Daniel C. Douek
  14. Adrian B. McDermott
  15. Pascal M. Lavoie

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

Background

Quantifying antibody reactivity against multiple SARS-CoV-2 antigens at the population level may help understand individual differences in COVID-19 severity. Pre-existing low antibody cross-reactivity may be particularly prevalent among childcare providers, including pediatric health care workers (HCW) who may be more exposed to circulating coronaviruses.

Methods

Cross-sectional study that included adults in the Vancouver area in British Columbia (BC), Canada, between May 17 and June 19, 2020. SARS-CoV-2 seroprevalence was ascertained by measuring total SARS-CoV-2 IgG/M/A antibodies against a recombinant spike (S1) protein and adjusted for bias due to false-positive and false-negative test results. A novel, high sensitivity multiplex assay was also used to profile IgG against four SARS-CoV-2 antigens, SARS-CoV and four circulating coronaviruses.

Findings

Among 276 participants (71% HCW), three showed evidence of direct viral exposure, yielding an adjusted seroprevalence of 0.60% [95%CI 0% – 2.71%], with no difference between HCW and non-HCW, or between paediatric and adult HCW. Among the 273 unexposed individuals, 7.3% [95%CI 4.5% – 11.1%], 48.7 [95%CI 42.7% – 54.8%] and 82.4% [95%CI 77.4% – 86.7%] showed antibody reactivity against SARS-CoV-2 RBD, N or Spike proteins, respectively. SARS-CoV-2 reactivity did not significantly correlate with age, sex, did not significantly differ between HCW and non-HCW (prevalence 1.0% vs 1.0%; P =1.00) and between pediatric and adult HCW (0.7% vs 1.6%; P =0.54), and modestly correlated with reactivity to circulating coronaviruses (Spearman rho range: 0.130 to 0.224 for 7 significant (FDR 5%), out of 16 correlations, from 36 correlations tested).

Interpretation

A substantial proportion of individuals showed low, but detectable antibody reactivity against SARS-CoV-2 antigens in this population despite low evidence of direct SARS-CoV-2 exposure.

Funding

NIAID/NIH

Article activity feed

  1. Version published to 10.1101/2020.10.05.20206664v7 on medRxiv
  2. Version published to 10.1101/2020.10.05.20206664v6 on medRxiv
  3. Version published to 10.1101/2020.10.05.20206664v5 on medRxiv
  4. ScreenIT

    SciScore for 10.1101/2020.10.05.20206664: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: To minimize recruitment bias, all adults who responded to the invitation email and returned their signed consent form were enrolled sequentially and invited to give a blood sample, without triaging.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Sulfo-tag-labelled anti-IgG detection antibody were added and the electrochemiluminescence signal was read using the MSD Sector 600 instrument.
    anti-IgG
    suggested: None
    Commercial chemiluminescent (CLIA) antibody assay: Total antibody (IgA, IgG and IgM) against recombinant spike (S1) protein was determined using the VITROS 5600 analyser (Ortho-Clinical Diagnostics, Rochester, NY) according to manufacturer instructions.
    IgA, IgG
    suggested: None
    S1
    suggested: None
    Software and Algorithms
    SentencesResources
    Analyses were conducted in R version 4.0.2, R Studio version 3.6.2 and GraphPad Prism version 8.4.
    GraphPad Prism
    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 limitations. First, due to the lack of follow-up, findings from this study should not be used to predict whether the antibody reactivity to SARS-CoV-2 in unexposed individuals may confer any immune protection or harm. Second, infection with SARS-CoV-2 prior to 7 days may be underestimated by serology (21). However, this is unlikely to have had a significant effect on our estimates considering the low number of reported cases in BC. Third, the small sample size limited the power for correlation analyses and the precision of estimates of the overall prevalence from a direct SARS-CoV-2 exposure. In conclusion, this study reveals that pre-existing antibody reactivity against SARS-CoV-2 antigens in sera from unexposed adults and in young infants is common, although it has been largely overlooked in previous serology studies. These findings warrant urgent studies of the impact such pre-existing seroreactivity may have on seroconversion following an exposure to SARS-CoV-2, likelihood of acquiring the infection, COVID-19 severity or vaccine responses.

    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.

  5. Version published to 10.1101/2020.10.05.20206664v3 on medRxiv
  6. Version published to 10.1101/2020.10.05.20206664v4 on medRxiv
  7. Version published to 10.1101/2020.10.05.20206664v2 on medRxiv
  8. Version published to 10.1101/2020.10.05.20206664v1 on medRxiv