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

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BACKGROUND: Understanding 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.

METHODS: RT-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.

RESULTS: Data 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 <18 years (OR = 0.55 [95% CI: 0.38-0.79]), versus 18-44 years, and for workplace (OR = 0.36 [95% CI: 0.23-0.55]) and social (OR = 0.44 [95% CI: 0.28-0.66]) contacts, versus household contacts. Higher transmission odds were observed for case-patient's spouses than other household contacts (OR = 2.25 [95% CI: 1.52-3.35]). Compared to index case-patients identified in the community, secondary case-patients identified through contract-tracing generated significantly fewer close contacts and secondary case-patients of their own. Transmission was heterogeneous, with 41% of index case-patients generating 81% of directly-linked secondary case-patients.

CONCLUSIONS: Given 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.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:18

Enthalten in:

PloS one - 18(2023), 6 vom: 10., Seite e0275125

Sprache:

Englisch

Beteiligte Personen:

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

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Date Completed 26.06.2023

Date Revised 18.11.2023

published: Electronic-eCollection

Citation Status MEDLINE

doi:

10.1371/journal.pone.0275125

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM358536588