Modelling the effectiveness and social costs of daily lateral flow antigen tests versus quarantine in preventing onward transmission of COVID-19 from traced contacts

  1. Luca Ferretti
  2. Chris Wymant
  3. Anel Nurtay
  4. Lele Zhao
  5. Robert Hinch
  6. David Bonsall
  7. Michelle Kendall
  8. Joanna Masel
  9. John Bell
  10. Susan Hopkins
  11. A. Marm Kilpatrick
  12. Tim Peto
  13. Lucie Abeler-Dörner
  14. Christophe Fraser

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Abstract

Quarantining close contacts of individuals infected with SARS-CoV-2 for 10 to 14 days is a key strategy in reducing transmission. However, quarantine requirements are often unpopular, with low adherence, especially when a large fraction of the population has been vaccinated. Daily contact testing (DCT), in which contacts are required to isolate only if they test positive, is an alternative to quarantine for mitigating the risk of transmission from traced contacts. In this study, we developed an integrated model of COVID-19 transmission dynamics and compared the strategies of quarantine and DCT with regard to reduction in transmission and social/economic costs (days of quarantine/self-isolation). Specifically, we compared 10-day quarantine to 7 days of self-testing using rapid lateral flow antigen tests, starting 3 days after exposure to a case. We modelled both incomplete adherence to quarantine and incomplete adherence to DCT. We found that DCT reduces transmission from contacts with similar effectiveness, at much lower social/economic costs, especially for highly vaccinated populations. The findings were robust across a spectrum of scenarios with varying assumptions on the speed of contact tracing, sensitivity of lateral flow antigen tests, adherence to quarantine and uptake of testing. Daily tests would also allow rapid initiation of a new round of tracing from infected contacts.

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  1. Rapid Reviews Infectious Diseases

    Timothy Russell

    Review 2: "Modelling the effectiveness and social costs of daily lateral flow antigen tests versus quarantine in preventing onward transmission of COVID-19 from traced contacts"

    This preprint models the use of daily antigen testing compared to quarantine of contacts for reducing transmission and socioeconomic costs. Reviewers deemed the model assumptions reasonable and the study's conclusions strong.

  2. Rapid Reviews Infectious Diseases

    Corey Peak

    Review 1: "Modelling the effectiveness and social costs of daily lateral flow antigen tests versus quarantine in preventing onward transmission of COVID-19 from traced contacts"

    This preprint models the use of daily antigen testing compared to quarantine of contacts for reducing transmission and socioeconomic costs. Reviewers deemed the model assumptions reasonable and the study's conclusions strong.

  4. ScreenIT

    SciScore for 10.1101/2021.08.06.21261725: (What is this?)

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

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    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: We detected the following sentences addressing limitations in the study:
    One limitation of our results is our simple metric for the cost-benefit ratio, defined as the number of days of self-isolation or quarantine per transmission averted, for an average traced contact. When either top-down or voluntary control measures keep R(t) near 1 (Weitz et al. 2020), this metric describes efficiency in achieving this outcome (Petrie and Masel 2020). Translating the number of days spent in quarantine/self-isolation into specific social/economic costs will vary according to settings. The costs are particularly large, making DCT especially beneficial, in settings where individuals are unable to work from home, have no effective place to self-isolate, or struggle to live independently (Smith et al. 2021), as well as in settings where many people are repeatedly affected, for example where entire school year groups are sent home or workplaces closed (Leng et al. 2021). On the other hand, if reduced transmission tips the balance from an uncontrolled to a controlled epidemic, then even strategies with much larger costs for only slightly larger benefits (both defined as above) are preferred. For the present comparison between quarantine and DCT for traced contacts, the benefits were similar but costs were very different, simplifying the recommendation in favor of DCT in scenarios where the aim is epidemic mitigation, rather than elimination. A further complication, given the low sensitivity of COVID-19 self-testing, is the need for clear communication. A negative re...

    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.
    • Thank you for including a protocol registration statement.

    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.

  5. Version published to 10.1101/2021.08.06.21261725v1 on medRxiv