Household transmission of the SARS-CoV-2 Omicron variant in Denmark

  1. Frederik Plesner Lyngse
  2. Laust Hvas Mortensen
  3. Matthew J. Denwood
  4. Lasse Engbo Christiansen
  5. Camilla Holten Møller
  6. Robert Leo Skov
  7. Katja Spiess
  8. Anders Fomsgaard
  9. Ria Lassaunière
  10. Morten Rasmussen
  11. Marc Stegger
  12. Claus Nielsen
  13. Raphael Niklaus Sieber
  14. Arieh Sierra Cohen
  15. Frederik Trier Møller
  16. Maria Overvad
  17. Kåre Mølbak
  18. Tyra Grove Krause
  19. Carsten Thure Kirkeby

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Abstract

In late 2021, the Omicron SARS-CoV-2 variant overtook the previously dominant Delta variant, but the extent to which this transition was driven by immune evasion or a change in the inherent transmissibility is currently unclear. We estimate SARS-CoV-2 transmission within Danish households during December 2021. Among 26,675 households (8,568 with the Omicron VOC), we identified 14,140 secondary infections within a 1–7-day follow-up period. The secondary attack rate was 29% and 21% in households infected with Omicron and Delta, respectively. For Omicron, the odds of infection were 1.10 (95%-CI: 1.00-1.21) times higher for unvaccinated, 2.38 (95%-CI: 2.23-2.54) times higher for fully vaccinated and 3.20 (95%-CI: 2.67-3.83) times higher for booster-vaccinated contacts compared to Delta. We conclude that the transition from Delta to Omicron VOC was primarily driven by immune evasiveness and to a lesser extent an inherent increase in the basic transmissibility of the Omicron variant.

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  1. Version published to 10.1038/s41467-022-33328-3
  2. ScreenIT

    SciScore for 10.1101/2021.12.27.21268278: (What is this?)

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

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    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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  3. Version published to 10.1101/2021.12.27.21268278v1 on medRxiv