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COVID-19 Case Investigation and Contact Tracing in New York City, June 1, 2020, to October 31, 2021

Educational Objective
To identify the key insights or developments described in this article
Key Points

Question  What were the outcomes of the COVID-19 contact tracing program in New York City?

Findings  In this cross-sectional study, a workforce of 4147 contact tracers attempted case investigations on 941 035 persons and contact interviews on 1 218 650 persons from June 1, 2020, to October 31, 2021. Overall expense from May 6, 2020, to October 31, 2021, was approximately $600 million.

Meaning  These results suggest that a large program can be rapidly developed, operationalized, and subsequently maintained.

Abstract

Importance  Contact tracing is a core strategy for preventing the spread of many infectious diseases of public health concern. Better understanding of the outcomes of contact tracing for COVID-19 as well as the operational opportunities and challenges in establishing a program for a jurisdiction as large as New York City (NYC) is important for the evaluation of this strategy.

Objective  To describe the establishment, scaling, and maintenance of Trace, NYC’s contact tracing program, and share data on outcomes during its first 17 months.

Design, Setting, and Participants  This cross-sectional study included people with laboratory test–confirmed and probable COVID-19 and their contacts in NYC between June 1, 2020, and October 31, 2021. Trace launched on June 1, 2020, and had a workforce of 4147 contact tracers, with the majority of the workforce performing their jobs completely remotely. Data were analyzed in March 2022.

Main Outcomes and Measures  Number and proportion of persons with COVID-19 and contacts on whom investigations were attempted and completed; timeliness of interviews relative to symptom onset or exposure for symptomatic cases and contacts, respectively.

Results  Case investigations were attempted for 941 035 persons. Of those, 840 922 (89.4%) were reached and 711 353 (75.6%) completed an intake interview (women and girls, 358 775 [50.4%]; 60 178 [8.5%] Asian, 110 636 [15.6%] Black, 210 489 [28.3%] Hispanic or Latino, 157 349 [22.1%] White). Interviews were attempted for 1 218 650 contacts. Of those, 904 927 (74.3%) were reached, and 590 333 (48.4%) completed intake (women and girls, 219 261 [37.2%]; 47 403 [8.0%] Asian, 98 916 [16.8%] Black, 177 600 [30.1%] Hispanic or Latino, 116 559 [19.7%] White). Completion rates were consistent over time and resistant to changes related to vaccination as well as isolation and quarantine guidance. Among symptomatic cases, median time from symptom onset to intake completion was 4.7 days; a median 1.4 contacts were identified per case. Median time from contacts’ last date of exposure to intake completion was 2.3 days. Among contacts, 30.1% were tested within 14 days of notification. Among cases, 27.8% were known to Trace as contacts. The overall expense for Trace from May 6, 2020, through October 31, 2021, was approximately $600 million.

Conclusions and Relevance  Despite the complexity of developing a contact tracing program in a diverse city with a population of over 8 million people, in this case study we were able to identify 1.4 contacts per case and offer resources to safely isolate and quarantine to over 1 million cases and contacts in this study period.

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Article Information

Accepted for Publication: September 8, 2022.

Published: November 2, 2022. doi:10.1001/jamanetworkopen.2022.39661

Open Access: This is an open access article distributed under the terms of the CC-BY-NC-ND License. © 2022 Blaney K et al. JAMA Network Open.

Corresponding Author: Kathleen Blaney, MPH, RN, New York City Department of Health and Mental Hygiene, 42-09 28th St, CN 5-22, Queens, NY 11101 (kathleen.blaney@gmail.com).

Author Contributions: Ms Blaney and Dr Foerster had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Blaney, Blake, Bray, Gindler, Johnson, Keeley, McKenney, Perl, Peters, Ray, Udeagu, Watkins, Zielinski, Long, Vora.

Acquisition, analysis, or interpretation of data: Blaney, Foerster, Baumgartner, Benckert, Chamany, Devinney, Fine, Gindler, Guerra, Lee, Lipsit, Misra, Ray, Saad, Thomas, Trieu, Wong, Long, Vora.

Drafting of the manuscript: Blaney, Long, Vora.

Critical revision of the manuscript for important intellectual content: Blaney, Foerster, Baumgartner, Benckert, Blake, Bray, Chamany, Devinney, Fine, Gindler, Guerra, Johnson, Keeley, Lee, Lipsit, McKenney, Misra, Perl, Peters, Ray, Saad, Thomas, Trieu, Udeagu, Watkins, Wong, Zielinski, Long, Vora.

Statistical analysis: Blaney, Foerster, Fine.

Obtained funding: Johnson, Vora.

Administrative, technical, or material support: Blaney, Baumgartner, Benckert, Blake, Bray, Chamany, Devinney, Fine, Gindler, Johnson, Keeley, Lee, Lipsit, McKenney, Misra, Perl, Peters, Ray, Saad, Thomas, Trieu, Udeagu, Watkins, Wong, Vora.

Supervision: Blaney, Bray, Gindler, Johnson, Udeagu, Long, Vora.

Conflict of Interest Disclosures: Dr Fine reported receiving grants from the US Centers for Disease Control in a cooperative agreement during the conduct of the study. Dr Watkins reported grants from Robert Wood Johnson Foundation outside the submitted work. No other disclosures were reported.

Additional Contributions: We thank the New York City Department of Health and Mental Hygiene, Health + Hospitals, and the Department of Information Technology staff who worked tirelessly to support Trace, as well as the T2 Community Advisory Board and the thousands of contact tracers who made this operation possible.

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