SARS-CoV-2 seroprevalence in students and teachers: a longitudinal study from May to October 2020 in German secondary schools

  1. Carolin Kirsten
  2. Manja Unrath
  3. Christian Lück
  4. Alexander H Dalpke
  5. Reinhard Berner
  6. Jakob Armann

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Abstract

To quantify the number of SARS-CoV-2 infections in secondary schools after their reopening in May 2020.

Design

Repeated SARS-CoV-2 seroprevalence study after the reopening of schools and 4 months later.

Setting

Secondary school in Dresden, Germany.

Participants

1538 students grades 8–12 and 507 teachers from 13 schools.

Interventions

Serial blood sampling and SARS-CoV-2 IgG antibody assessment.

Primary and secondary outcome measure

Seroprevalence of SARS-CoV-2 antibodies in study population. Number of undetected cases.

Results

1538 students and 507 teachers were initially enrolled, and 1334 students and 445 teachers completed both study visits. The seroprevalence for SARS-CoV-2 antibodies was 0.6% in May/June and the same in September/October. Even in schools with reported COVID-19 cases before the lockdown of 13 March, no clusters could be identified. Of 12 persons with positive serology five had a known history of confirmed COVID-19; 23 out of 24 participants with a household history of COVID-91 were seronegative.

Conclusions

Schools do not play a crucial role in driving the SARS-CoV-2 pandemic in a low-prevalence setting. Transmission in families occurs very infrequently, and the number of unreported cases is low in this age group. These observations do not support school closures as a strategy fighting the pandemic in a low-prevalence setting.

Trial registration number

DRKS00022455.

Article activity feed

  1. Version published to 10.1136/bmjopen-2021-049876
  2. Version published to 10.1101/2020.07.16.20155143v4 on medRxiv
  3. Version published to 10.1101/2020.07.16.20155143v3 on medRxiv
  4. ScreenIT

    SciScore for 10.1101/2020.07.16.20155143: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: After teachers, students, and their legal guardians provided informed consent, 5 mL of peripheral venous blood were collected from each individual during visits at each participating school between May 25th and June 30th, 2020.
    IRB: Approval: The SchoolCoviDD19 study was approved by the Ethics Committee of the Technische Universität (TU) Dresden (BO-EK-156042020) and was registered on July 23rd 2020 and assigned the clinical trial number DRKS00022455.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Laboratory Analysis: We assessed SARS-CoV-2 IgG antibodies in all samples using a commercially available chemiluminescence immunoassay (CLIA) technology for the quantitative determination of anti-S1 and anti-S2 specific IgG antibodies to SARS-CoV-2 (Diasorin LIAISON® SARS-CoV-2 S1/S2 IgG Assay).
    SARS-CoV-2 IgG
    suggested: None
    anti-S1
    suggested: None
    anti-S2 specific IgG
    suggested: None
    All samples with a positive or equivocal LIAISON® test result, as well as all samples from participants with a reported personal or household history of a SARS-CoV-2 infection, were re-tested with two additional serological tests: These were a chemiluminescent microparticle immunoassay (CMIA) intended for the qualitative detection of IgG antibodies to the nucleocapsid protein of SARS-CoV-2 (Abbott Diagnostics® ARCHITECT SARS-CoV-2 IgG) (an index (S/C) of < 1.4 was considered negative whereas one >/= 1.4 was considered positive) and an ELISA detecting IgG against the S1 domain of the SARS-CoV-2 spike protein (Euroimmun® Anti-SARS-CoV-2 ELISA) (a ratio < 0.8 was considered negative, 0.8–1.1 equivocal, > 1.1 positive) Participants whose positive or equivocal LIAISON® test result could be confirmed by a positive test result in at least one additional serological test were considered having antibodies against SARS-CoV-2.
    Anti-SARS-CoV-2 ELISA
    suggested: None
    SARS-CoV-2
    suggested: None
    Software and Algorithms
    SentencesResources
    All samples with a positive or equivocal LIAISON® test result, as well as all samples from participants with a reported personal or household history of a SARS-CoV-2 infection, were re-tested with two additional serological tests: These were a chemiluminescent microparticle immunoassay (CMIA) intended for the qualitative detection of IgG antibodies to the nucleocapsid protein of SARS-CoV-2 (Abbott Diagnostics® ARCHITECT SARS-CoV-2 IgG) (an index (S/C) of < 1.4 was considered negative whereas one >/= 1.4 was considered positive) and an ELISA detecting IgG against the S1 domain of the SARS-CoV-2 spike protein (Euroimmun® Anti-SARS-CoV-2 ELISA) (a ratio < 0.8 was considered negative, 0.8–1.1 equivocal, > 1.1 positive) Participants whose positive or equivocal LIAISON® test result could be confirmed by a positive test result in at least one additional serological test were considered having antibodies against SARS-CoV-2.
    Abbott
    suggested: (Abbott, RRID:SCR_010477)
    Statistical Analysis: Analyses were performed using IBM SPSS 25.0 and Microsoft Excel 2010.
    SPSS
    suggested: (SPSS, RRID:SCR_002865)
    Microsoft Excel
    suggested: (Microsoft Excel, RRID:SCR_016137)

    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.

    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 10.1101/2020.07.16.20155143v1 on medRxiv
  6. Version published to 10.1101/2020.07.16.20155143v2 on medRxiv