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

Ajay K Sethi; Cristalyne Bell; Derek Norton; Maureen D Goss; Shari Barlow; Guanhua Chen; Amra Uzicanin; Jonathan L Temte

doi:10.1111/irv.70031

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

Influenza Other Respir Viruses. 2024 Nov;18(11):e70031. doi: 10.1111/irv.70031.

Authors

Ajay K Sethi¹, Cristalyne Bell², Derek Norton³, Maureen D Goss², Shari Barlow², Guanhua Chen³, Amra Uzicanin⁴, Jonathan L Temte²

Affiliations

¹ Department of Population Health Sciences, University of Wisconsin, Madison, Wisconsin, USA.
² Department of Family Medicine and Community Health, University of Wisconsin, Madison, Wisconsin, USA.
³ Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, Wisconsin, USA.
⁴ National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

Abstract

Background: Household transmission of SARS-CoV-2 is a driver of the ongoing COVID-19 pandemic. Understanding factors that contribute to secondary infection risks (SIRs) 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% nonbinary; 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 with 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 a 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 and vaccination) to reduce future transmission risk.

Keywords: SARS‐CoV‐2; genomics; household transmission; respiratory disease surveillance.

Publication types

Research Support, U.S. Gov't, P.H.S.

MeSH terms

Adolescent
Adult
COVID-19* / epidemiology
COVID-19* / transmission
Child
Child, Preschool
Family Characteristics*
Female
Humans
Male
Middle Aged
Prospective Studies
Risk Factors
SARS-CoV-2* / genetics
SARS-CoV-2* / isolation & purification
Wisconsin / epidemiology
Young Adult

Abstract

Publication types

MeSH terms

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