PLoS ONE (Jan 2023)

Epidemiology of SARS-CoV-2 transmission and superspreading in Salt Lake County, Utah, March-May 2020.

  • Joseph Walker,
  • Tiffany Tran,
  • Brooke Lappe,
  • Paul Gastanaduy,
  • Prabasaj Paul,
  • Ian T Kracalik,
  • Victoria L Fields,
  • Adriana Lopez,
  • Amy Schwartz,
  • Nathaniel M Lewis,
  • Jacqueline E Tate,
  • Hannah L Kirking,
  • Aron J Hall,
  • Eric Pevzner,
  • Ha Khong,
  • Maureen Smithee,
  • Jason Lowry,
  • Angela Dunn,
  • Tair Kiphibane,
  • Cuc H Tran

DOI
https://doi.org/10.1371/journal.pone.0275125
Journal volume & issue
Vol. 18, no. 6
p. e0275125

Abstract

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BackgroundUnderstanding the drivers of SARS-CoV-2 transmission can inform the development of interventions. We evaluated transmission identified by contact tracing investigations between March-May 2020 in Salt Lake County, Utah, to quantify the impact of this intervention and identify risk factors for transmission.MethodsRT-PCR positive and untested symptomatic contacts were classified as confirmed and probable secondary case-patients, respectively. We compared the number of case-patients and close contacts generated by different groups, and used logistic regression to evaluate factors associated with transmission.ResultsData were collected on 184 index case-patients and up to six generations of contacts. Of 1,499 close contacts, 374 (25%) were classified as secondary case-patients. Decreased transmission odds were observed for contacts aged ConclusionsGiven sufficient resources and complementary public health measures, contact tracing can contain known chains of SARS-CoV-2 transmission. Transmission is associated with age and exposure setting, and can be highly variable, with a few infections generating a disproportionately high share of onward transmission.