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Factors associated with transmission across three waves of SARS-COV-2 in a prospective community-based study of households with school-aged children -- Dane County, Wisconsin, 2020-2022
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  • Sethi AK,
  • Cristalyne Bell,
  • Derek Norton,
  • Maureen Goss,
  • Shari Barlow,
  • Guanhua Chen,
  • Amra Uzicanin,
  • Jonathan Temte
Sethi AK
University of Wisconsin-Madison Department of Population Health Sciences
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Cristalyne Bell
University of Wisconsin-Madison Department of Family Medicine and Community Health
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Derek Norton
University of Wisconsin-Madison Department of Biostatistics and Medical Informatics
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Maureen Goss
University of Wisconsin-Madison Department of Family Medicine and Community Health
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Shari Barlow
University of Wisconsin-Madison Department of Family Medicine and Community Health
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Guanhua Chen
University of Wisconsin-Madison Department of Biostatistics and Medical Informatics
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Amra Uzicanin
Centers for Disease Control and Prevention
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Jonathan Temte
University of Wisconsin-Madison Department of Family Medicine and Community Health

Corresponding Author:[email protected]

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Abstract

Background: Household transmission of SARS-CoV-2 is a driver of the ongoing COVID-19 pandemic. Understanding factors that contribute to secondary infection rates (SIR) can define changing trends and inform public health policies. Methods: The ORegon CHild Absenteeism due to Respiratory Disease Study (ORCHARDS) prospectively monitors respiratory viruses within the Oregon School District (OSD) in southcentral Wisconsin. Households with students who had ≥2 respiratory symptoms were eligible and opted to participate in ORCHARDS. Between October 28, 2020, and May 16, 2022, all household members provided self-collected nasal specimens on days 0, 7, and 14 for SARS-CoV-2 detection using real-time reverse-transcription-polymerase chain reaction. We used logistic regression to investigate individual- and household-level characteristics associated with SARS-CoV-2 transmission. Results: Overall, 127 households comprising 572 individuals (48% female; 52% male; 0.4% non-binary; 77% >18 years) had at least one detection of SARS-CoV-2. The overall SIR was 47% and decreased over time (pre-Delta=72% [95%CI: 58%-83%]; Delta=51% [40%-63%]; and Omicron=41% [36%-47%]. Odds of household transmission were 63% lower during the Omicron period compared to the pre-Delta period (OR=0.36 [95%CI: 0.13-0.94] P=0.037). Greater household density (members/bedroom) was significantly associated with household transmission during the Omicron period (OR=6.8, [2.19-21.37] P=0.001). Index case age, illness severity, and individual symptoms were not significantly associated with odds of household transmission. Conclusions: Greater household density was associated with higher risk of SARS-CoV-2 transmission, but the risk declined over time with subsequent variants. Interplay between variants, prior infection, and individual/household factors may identify modifiable factors (e.g., behavior, vaccination) to reduce future transmission risk.
Submitted to Influenza and other respiratory viruses
12 Jun 2024Review(s) Completed, Editorial Evaluation Pending
12 Jun 2024Editorial Decision: Revise Major
30 Jul 20241st Revision Received
01 Aug 2024Submission Checks Completed
01 Aug 2024Assigned to Editor
03 Sep 2024Reviewer(s) Assigned
09 Oct 2024Review(s) Completed, Editorial Evaluation Pending
12 Oct 2024Editorial Decision: Accept