Large-scale seroepidemiologic surveillance of COVID-19 - Cross-sectional study in Hyogo prefecture of Japan in August, 2021

  1. Zhenxiao Ren
  2. Koichi Furukawa
  3. Mitsuhiro Nishimura
  4. Yukiya Kurahashi
  5. Silvia Sutandhio
  6. Lidya Handayani Tjan
  7. Kaito Aoki
  8. Natsumi Hasegawa
  9. Jun Arii
  10. Kenichi Uto
  11. Keiji Matsui
  12. Itsuko Sato
  13. Jun Saegusa
  14. Nonoka Godai
  15. Kohei Takeshita
  16. Masaki Yamamoto
  17. Tatsuya Nagashima
  18. Yasuko Mori

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Abstract

The situation of the COVID-19 pandemic in Japan is drastically changing in the 2 nd year, 2021, due to the appearance of SARS-CoV-2 variants of concern and the roll-out of mass vaccination. In addition to PCR diagnosis, periodic seroepidemiologic surveillance is important to analyze the epidemic situation. In this study, we analyzed the rate of seropositivity for the SARS-CoV-2 N and S antigens in Hyogo prefecture, Japan in August 2021. Sera collected from people who received a health check-up in a clinic of the Hyogo Prefecture Health Promotion Association were subjected to analysis of reactivity to the SARS-CoV-2 N and S antigens by electrochemiluminescence immunoassay (ECLIA) and enzyme-linked immunosorbent assay (ELISA), respectively. For a total 1,000 sera, the positive rates to N and S antigens were 2.1% and 38.7%, respectively. The infectious rate estimated by serological analysis based on the presence of the anti-N antibody was 2.5-fold higher than the value reported based on PCR-based analysis, and it increased five-fold compared to the rate determined by our previous seroepidemiologic study in October, 2020. The anti-S positive rate was almost consistent with the vaccination rate in this area. The observed high anti-S antibody level in the seropositive population may indicate that the mass vaccination in Japan is being performed smoothly at this time point, although the infectious rate has also increased.

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  1. ScreenIT

    SciScore for 10.1101/2021.09.26.21264129: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: Ethics statement: This study was approved by the ethical committees of Kobe University Graduate School of Medicine (approval codes: B2156702).
    Consent: To validate the ELISA, sera from COVID-19 patients and healthy volunteers were used under approval of the ethical committee of Kobe University Graduate School of Medicine (approval code B200200), and written informed consent was obtained from the donors.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Detection of anti-N antibody by electrochemiluminescence immunoassay (ECLIA): An electrochemiluminescence immunoassay (ECLIA) was conducted using the cobas e801 module (Roche Diagnostics, Rotkreuz, Switzerland) as in our previous study (11).
    anti-N
    suggested: None
    Detection of anti-Spike antibodies by enzyme-linked immunosorbent assay (ELISA): Anti-Spike antibodies in the human sera were detected by an enzyme-linked immunosorbent assay with the purified Spike ectodomain described above.
    anti-Spike
    suggested: None
    ELISA)
    suggested: None
    After washing with PBST, a goat anti-human IgG with conjugated horseradish peroxidase (abcam) diluted 1:10000 with PBST was added as a secondary antibody followed by incubation at 37°C for 1 hour.
    anti-human IgG
    suggested: None
    The value of the area under the curve (AUC) was used to evaluate the anti-S antibody amount (6, 12).
    anti-S
    suggested: None
    Recombinant DNA
    SentencesResources
    Briefly, the gene sequence of the SARS-CoV-2 Spike ectodomain (amino acids 1-1213) was subcloned into a pCAGGS vector (24) with a puromycin-resistant gene.
    pCAGGS
    suggested: RRID:Addgene_18926)

    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.

  2. Version published to 10.1101/2021.09.26.21264129v1 on medRxiv