SARS‐CoV‐2 prevalence and transmission in swimming activities: Results from a retrospective cohort study

  1. Martin Brink Termansen
  2. Ask Vest Christiansen
  3. Sebastian Frische

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Abstract

There is an urgent need for research on the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) causing coronavirus disease 2019 (COVID‐19), as the transmissibility differs between settings and populations. Here we report on a questionnaire‐based retrospective cohort study of the prevalence and transmission of SARS‐CoV‐2 among participants in swimming activities in Denmark in the last 5 months of 2020 during the COVID‐19 pandemic.

Eight of 162 swimming activities with a SARS‐CoV‐2 positive participant led to transmission to 23 other participants. Overall, the percentage of episodes leading to transmission was 4.9% (competitive swimming 8.9%; recreational swimming 1.3%). Overall, the incidence rate of transmission was 19.5 participants per 100 000 pool activity hours (corresponding values: 43.5 and 4.7 for competitive and recreational swimming, respectively).

Compliance with precautionary restrictions was highest regarding hand hygiene (98.1%) and lowest in distancing personal sports bags (69.9%). As a result of low statistical power, the study showed no significant effect of restrictions.

Insight into the risk of transmission of SARS‐CoV‐2 during indoor swimming is needed to estimate the efficiency of restrictive measures on this and other sports and leisure activities. Only when we know how the virus spreads through various settings, optimal strategies to handle the COVID‐19 pandemic can be developed.

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  1. Version published to 10.1111/sms.14071
  2. ScreenIT

    SciScore for 10.1101/2021.03.19.21253351: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Data processing and statistical analysis: Data were analyzed using Microsoft Excel v.
    Microsoft Excel
    suggested: (Microsoft Excel, RRID:SCR_016137)
    . 16.43 for Mac (Microsoft Corporation, Seattle, WA) and statistical analyses were conducted with Stata/IC v. 16.1 for Mac (StataCorp LCC, College Station, TX).
    StataCorp
    suggested: (Stata, RRID:SCR_012763)
    Figures were made using GraphPad Prism version 9.0.2 for Mac (GraphPad Software, San Diego, CA) or Lucidchart (www.lucidchart.com).
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)

    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:
    Due to methodological limitations, the apparent difference between competitive swimming and recreational swimming should be interpreted with caution (see limitations below). As the risk episodes exposed on average 13.6 (95% CI: 11.9;15.3) participants to SARS-CoV-2, in total 2,201 (95% CI: 1,923;2,479) swimmers are estimated to have been exposed to SARS-CoV-2 at the recorded risk episodes. Of these swimmers, 23 subsequently tested positive for SARS-CoV-2, leading to an estimated risk of infection of 1.0 (95% CI: 0.9;1.2)% by participating in a risk episode. This number is an estimate of a participant’s risk of getting infected with SARS-CoV-2 at an indoor swimming activity (under the restrictions prevailing in the study period) if another participant is SARS-CoV-2 positive. For comparison, a cohort study showed SARS-CoV-2 transmission from non-hospitalized COVID-19 patients to 12-24% of close contacts, i.e. health care-workers, household contacts, nursing home workers or residents[17]. Further, an observational study of Danish households showed SARS-CoV-2 transmission to 48% of household residents 14 days after the primary case tested positive[18]. Competitive swimming comprises less than 5% of DSF members but accounted for an estimated 39.4% of the three swimming activity categories’ pool activity hours during the period under study. When normalizing to pool activity hours the incidence rate analysis also suggests there was a higher rate of transmission during competitive sw...

    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.
    • No funding statement was detected.
    • No protocol registration statement was detected.

    About SciScore

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  3. Version published to 10.1101/2021.03.19.21253351v1 on medRxiv