Germany’s low SARS-CoV-2 seroprevalence confirms effective containment in 2020: Results of the nationwide RKI-SOEP study

  1. Hannelore Neuhauser
  2. Angelika Schaffrath Rosario
  3. Hans Butschalowsky
  4. Sebastian Haller
  5. Jens Hoebel
  6. Janine Michel
  7. Andreas Nitsche
  8. Christina Poethko-Müller
  9. Franziska Prütz
  10. Martin Schlaud
  11. Hans W. Steinhauer
  12. Hendrik Wilking
  13. Lothar H. Wieler
  14. Lars Schaade
  15. Stefan Liebig
  16. Antje Gößwald
  17. Markus M. Grabka
  18. Sabine Zinn
  19. Thomas Ziese

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Abstract

Pre-vaccine SARS-CoV-2 seroprevalence data from Germany are scarce outside hotspots, and socioeconomic disparities remained largely unexplored. The nationwide RKI-SOEP study with 15,122 adult participants investigated seroprevalence and testing in a supplementary wave of the Socio-Economic-Panel conducted predominantly in October-November 2020. Self-collected oral-nasal swabs were PCR-positive in 0.4% and Euroimmun anti-SARS-CoV-2-S1-IgG ELISA from dry capillary blood in 1.3% (95% CI 0.9-1.7%, population-weighted, corrected for sensitivity=0.811, specificity=0.997). Seroprevalence was 1.7% (95% CI 1.2-2.3%) when additionally adjusting for antibody decay. Overall infection prevalence including self-reports was 2.1%. We estimate 45% (95% CI 21-60%) undetected cases and analyses suggest lower detection in socioeconomically deprived districts. Prior SARS-CoV-2 testing was reported by 18% from the lower educational group compared to 25% and 26% from the medium and high educational group (p<0.0001). Symptom-triggered test frequency was similar across educational groups. However, routine testing was more common in low-educated adults, whereas travel-related testing and testing after contact with an infected person was more common in highly educated groups. In conclusion, pre-vaccine SARS-CoV-2-seroprevalence in Germany was very low. Notified cases appear to capture more than half of infections but may underestimate infections in lower socioeconomic groups. These data confirm the successful containment strategy of Germany until winter 2020.

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  1. ScreenIT

    SciScore for 10.1101/2021.11.22.21266711: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: Approval was obtained from the ethics committee of the Berlin Doctors’ Council (reference ID Eth-33/20).
    Consent: All participants provided informed consent.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    BlindingThe number of infections missed by the mandatory notification system was estimated in two ways: first internally, by estimating the proportion of seropositive cases that was unaware of the infection (Table 2) and second by comparing the seroprevalence observed in the study, adjusted for test characteristics, to the number of notified cases, adjusted for sampling density (Table 3 and Table S3).
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Standardized punches of DBS (DBS Puncher, PerkinElmer, Waltham MA, USA) were extracted according to the manufacturer’s protocol (Euroimmun AG, Lübeck, Germany) and tested for SARS-CoV-2 anti-S1 IgG antibodies using lots E200518BC (from Oct 12th to Dec 2nd, 2020) and E200831BC (from Dec 3rd, 2020 to end of study) of the Anti-SARS-CoV-2-ELISA (IgG) (Euroimmun AG, Lübeck, Germany).
    anti-S1 IgG
    suggested: (Imported from the IEDB Cat# 2E10, RRID:AB_2848047)
    Anti-SARS-CoV-2-ELISA ( IgG
    suggested: None
    Both RKI laboratories have successfully participated in external quality assessments (EQAs) on the detection of SARS-CoV-2 genome and/or SARS-CoV-2 IgG antibodies, offered by INSTAND (INSTAND, Düsseldorf, Germany)
    SARS-CoV-2 IgG
    suggested: None
    The overall infection status was considered positive if at least one of the three indicators (PCR result from the ONS, IgG antibody result from the DBS, or self-reported pre-study SARS-CoV-2 test) was positive.
    IgG
    suggested: None
    Software and Algorithms
    SentencesResources
    Analyses were performed with SAS 9.4 (SAS Institute Inc.
    SAS Institute
    suggested: (Statistical Analysis System, RRID:SCR_008567)

    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 10.1101/2021.11.22.21266711v1 on medRxiv