Dynamics of anti-SARS-CoV-2 seroconversion in individual patients and at the population level

  1. Alina Szewczyk-Dąbrowska
  2. Wiktoria Budziar
  3. Krzysztof Baniecki
  4. Aleksandra Pikies
  5. Marek Harhala
  6. Natalia Jędruchniewicz
  7. Zuzanna Kaźmierczak
  8. Katarzyna Gembara
  9. Tomasz Klimek
  10. Wojciech Witkiewicz
  11. Artur Nahorecki
  12. Kamil Barczyk
  13. Urszula Grata-Borkowska
  14. Krystyna Dąbrowska

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

The immune response and specific antibody production in COVID-19 are among the key factors that determine both prognostics for individual patients and the global perspective for controlling the pandemics. So called “dark figure”, that is, a part of population that has been infected but not registered by the health care system, make it difficult to estimate herd immunity and to predict pandemic trajectories. Here we present a follow up study of population screening for hidden herd immunity to SARS-CoV-2 in individuals who had never been positively diagnosed against SARS-CoV-2; the first screening was in May 2021, and the follow up in December 2021. We found that specific antibodies targeting SARS-CoV-2 detected in May as the “dark figure” cannot be considered important 7 months later due to their significant drop. On the other hand, among participants who at the first screening were negative for anti-SARS-CoV-2 IgG, and who have never been diagnosed for SARS-CoV-2 infection nor vaccinated, 26% were found positive for anti-SARS-CoV-2 IgG. This can be attributed to of the “dark figure” of the recent, fourth wave of the pandemic that occurred in Poland shortly before the study in December. Participants who were vaccinated between May and December demonstrated however higher levels of antibodies, than those who undergone mild or asymptomatic (thus unregistered) infection. Only 7% of these vaccinated participants demonstrated antibodies that resulted from infection (anti-NCP). The highest levels of protection were observed in the group that had been infected with SARS-CoV-2 before May 2021 and also fully vaccinated between May and December. These observations demonstrate that the hidden fraction of herd immunity is considerable, however its potential to suppress the pandemics is limited, highlighting the key role of vaccinations.

Article activity feed

  1. Version published to 10.1371/journal.pone.0274095
  2. ScreenIT

    SciScore for 10.1101/2022.03.20.22272651: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: During the individual interview, all information about the study was provided and written consent was obtained from each participant.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Out of 501 people screened for SARS-CoV-2 antibodies in May 2021, 109 people were included in the follow-up study, considering previous serological status as identified in the first study, status of vaccination, their availability and agreement to participate in the repeated testing.
    SARS-CoV-2
    suggested: None
    The following groups were selected: Group 1 (N-, V-): Participants seronegative for SARS-CoV-2 antibodies in May 2021 (anti-NCP-negative), non-vaccinated; N=38 Group 2 (N-, V+): Participants seronegative for SARS-CoV-2 antibodies in May 2021 (anti-NCP-negative), fully vaccinated before December 2021; N=29 Group 3 (N+, V-): Participants seropositive for SARS-CoV-2-specific IgG antibodies in May 2021 (anti-NCP-IgG positive) and non-vaccinated; N=25 Group 4 (N+, V+): Participants seropositive for SARS-CoV-2-specific IgG antibodies in May 2021 (anti-NCP-IgG positive), fully vaccinated before December 2021; N=17 Of note, all vaccinated participants took the vaccination individually; therefore they could be vaccinated at different time points within May and December, and with different types of vaccines; most of them were vaccinated with the Pfizer vaccine (65%, 30 out of 46).
    anti-NCP-negative
    suggested: None
    anti-NCP-IgG positive
    suggested: None
    SARS-CoV-2-specific IgG
    suggested: None
    anti-NCP-IgG
    suggested: None
    Software and Algorithms
    SentencesResources
    Statistical analyses were performed by GraphPad Prism 9.
    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: 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.

    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 10.1101/2022.03.20.22272651v1 on medRxiv