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COVID-19 Case Investigation and Contact Tracing in the US, 2020

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

Question  What proportion of persons with laboratory-confirmed COVID-19 and their contacts are reached for case investigation and contact tracing?

Findings  In this surveillance-based, cross-sectional study, 2 of 3 individuals with COVID-19 were either not reached for interview or named no contacts when interviewed. A mean of 0.7 contacts were reached by telephone by public health authorities, and only 0.5 contacts per case were monitored, a lower rate than needed to overcome the estimated global SARS-CoV-2 reproductive number.

Meaning  The findings of this study suggest that current contact tracing practice had suboptimal impact on SARS-CoV-2 transmission.

Abstract

Importance  Contact tracing is a multistep process to limit SARS-CoV-2 transmission. Gaps in the process result in missed opportunities to prevent COVID-19.

Objective  To quantify proportions of cases and their contacts reached by public health authorities and the amount of time needed to reach them and to compare the risk of a positive COVID-19 test result between contacts and the general public during 4-week assessment periods.

Design, Setting, and Participants  This cross-sectional study took place at 13 health departments and 1 Indian Health Service Unit in 11 states and 1 tribal nation. Participants included all individuals with laboratory-confirmed COVID-19 and their named contacts. Local COVID-19 surveillance data were used to determine the numbers of persons reported to have laboratory-confirmed COVID-19 who were interviewed and named contacts between June and October 2020.

Main Outcomes and Measures  For contacts, the numbers who were identified, notified of their exposure, and agreed to monitoring were calculated. The median time from index case specimen collection to contact notification was calculated, as were numbers of named contacts subsequently notified of their exposure and monitored. The prevalence of a positive SARS-CoV-2 test among named and tested contacts was compared with that jurisdiction’s general population during the same 4 weeks.

Results  The total number of cases reported was 74 185. Of these, 43 931 (59%) were interviewed, and 24 705 (33%) named any contacts. Among the 74 839 named contacts, 53 314 (71%) were notified of their exposure, and 34 345 (46%) agreed to monitoring. A mean of 0.7 contacts were reached by telephone by public health authorities, and only 0.5 contacts per case were monitored. In general, health departments reporting large case counts during the assessment (≥5000) conducted smaller proportions of case interviews and contact notifications. In 9 locations, the median time from specimen collection to contact notification was 6 days or less. In 6 of 8 locations with population comparison data, positive test prevalence was higher among named contacts than the general population.

Conclusions and Relevance  In this cross-sectional study of US local COVID-19 surveillance data, testing named contacts was a high-yield activity for case finding. However, this assessment suggests that contact tracing had suboptimal impact on SARS-CoV-2 transmission, largely because 2 of 3 cases were either not reached for interview or named no contacts when interviewed. These findings are relevant to decisions regarding the allocation of public health resources among the various prevention strategies and for the prioritization of case investigations and contact tracing efforts.

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Article Information

Accepted for Publication: April 20, 2021.

Published: June 3, 2021. doi:10.1001/jamanetworkopen.2021.15850

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Lash RR et al. JAMA Network Open.

Corresponding Author: John E. Oeltmann, PhD, COVID-19 Response Team, Centers for Disease Control and Prevention, 1600 Clifton RD NE, Mailstop E-10, Atlanta, GA 30333 (joeltmann@cdc.gov).

Author Contributions: Dr Oeltmann had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Lash, Moonan, Donovan, Cieslak, Fleischauer, Goddard, Oeltmann.

Acquisition, analysis, or interpretation of data: Lash, Moonan, Byers, Bonacci, Bonner, Donahue, Donovan, Grome, Janssen, Magleby, McLaughlin, Miller, Pratt, Steinberg, Varela, Anschuetz, Cieslak, Fialkowski, Fleischauer, Johnson, Morris, Moses, Newman, Prinzing, Sulka, Va, Willis, Oeltmann.

Drafting of the manuscript: Lash, Moonan, Donahue, Fleischauer, Newman, Va, Oeltmann.

Critical revision of the manuscript for important intellectual content: Lash, Moonan, Byers, Bonacci, Bonner, Donahue, Donovan, Grome, Janssen, Magleby, McLaughlin, Miller, Pratt, Steinberg, Varela, Anschuetz, Cieslak, Fialkowski, Fleischauer, Goddard, Johnson, Morris, Moses, Prinzing, Sulka, Willis, Oeltmann.

Statistical analysis: Lash, Moonan, Bonacci, Donovan, Magleby, Miller, Varela, Fialkowski, Fleischauer, Johnson, Newman, Va, Oeltmann.

Administrative, technical, or material support: Lash, Moonan, Byers, Donovan, Janssen, McLaughlin, Miller, Steinberg, Varela, Goddard, Oeltmann.

Supervision: Lash, Moonan, Cieslak, Fleischauer, Oeltmann.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported by funding from the US Centers for Disease Control and Prevention.

Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

COVID-19 Contact Tracing Assessment Team Collaborators: The COVID-19 Contact Tracing Assessment Team members are listed in Supplement 2.

Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

Additional Contributions: Jordan Moody, MA (Public Health Associate Program, Centers for Disease Control and Prevention, assigned to Metro Nashville Public Health Department), Ariane Peralta, PhD (East Carolina University), Kathrine Tan, MD, MPH (Centers for Disease Control and Prevention), and Sherry Farr, PhD (Centers for Disease Control and Prevention) provided technical assistance. These individuals were not compensated for their contributions.

References
1.
US Food and Drug Administration. Coronavirus (COVID-19) update: FDA issues emergency use authorization for potential COVID-19 treatment. Published May 1, 2020. Accessed February 3, 2021. https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-issues-emergency-use-authorization-potential-covid-19-treatment
2.
Flaxman  S , Mishra  S , Gandy  A ,  et al; Imperial College COVID-19 Response Team.  Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe.   Nature. 2020;584(7820):257-261. doi:10.1038/s41586-020-2405-7PubMedGoogle ScholarCrossref
3.
Leung  CC , Lam  TH , Cheng  KK .  Mass masking in the COVID-19 epidemic: people need guidance.   Lancet. 2020;395(10228):945-947. doi:10.1016/S0140-6736(20)30520-1PubMedGoogle ScholarCrossref
4.
Kanu  FA , Smith  EE , Offutt-Powell  T , Hong  R , Dinh  TH , Pevzner  E ; Delaware Case Investigation and Contact Tracing Teams3.  Declines in SARS-CoV-2 transmission, hospitalizations, and mortality after implementation of mitigation measures—Delaware, March–June 2020.   MMWR Morb Mortal Wkly Rep. 2020;69(45):1691-1694. doi:10.15585/mmwr.mm6945e1PubMedGoogle ScholarCrossref
5.
Kucharski  AJ , Klepac  P , Conlan  AJK ,  et al; CMMID COVID-19 Working Group.  Effectiveness of isolation, testing, contact tracing, and physical distancing on reducing transmission of SARS-CoV-2 in different settings: a mathematical modelling study.   Lancet Infect Dis. 2020;20(10):1151-1160. doi:10.1016/S1473-3099(20)30457-6PubMedGoogle ScholarCrossref
6.
Keeling  MJ , Hollingsworth  TD , Read  JM .  Efficacy of contact tracing for the containment of the 2019 novel coronavirus (COVID-19).   J Epidemiol Community Health. 2020;74(10):861-866. doi:10.1101/2020.02.14.20023036PubMedGoogle Scholar
7.
Peak  CM , Kahn  R , Grad  YH ,  et al.  Individual quarantine versus active monitoring of contacts for the mitigation of COVID-19: a modelling study.   Lancet Infect Dis. 2020;20(9):1025-1033. doi:10.1016/S1473-3099(20)30361-3PubMedGoogle ScholarCrossref
8.
Hellewell  J , Abbott  S , Gimma  A ,  et al; Centre for the Mathematical Modelling of Infectious Diseases COVID-19 Working Group.  Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts.   Lancet Glob Health. 2020;8(4):e488-e496. doi:10.1016/S2214-109X(20)30074-7PubMedGoogle ScholarCrossref
9.
US Centers for Disease Control and Prevention. Interim guidance on developing a COVID-19 case investigation & contact tracing plan: overview. Updated February 18, 2021. Accessed February 3, 2021. https://www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/overview.html
10.
Weis  S .  Contact investigations: how do they need to be designed for the 21st century?   Am J Respir Crit Care Med. 2002;166(8):1016-1017. doi:10.1164/rccm.2207007PubMedGoogle ScholarCrossref
11.
Gandhi  M , Yokoe  DS , Havlir  DV .  Asymptomatic transmission, the Achilles’ heel of current strategies to control COVID-19.   N Engl J Med. 2020;382(22):2158-2160. doi:10.1056/NEJMe2009758PubMedGoogle ScholarCrossref
12.
Johansson  MA , Quandelacy  TM , Kada  S ,  et al.  SARS-CoV-2 transmission from people without COVID-19 symptoms.   JAMA Netw Open. 2021;4(1):e2035057. doi:10.1001/jamanetworkopen.2020.35057PubMedGoogle Scholar
13.
Yanes-Lane  M , Winters  N , Fregonese  F ,  et al.  Proportion of asymptomatic infection among COVID-19 positive persons and their transmission potential: a systematic review and meta-analysis.   PLoS One. 2020;15(11):e0241536. doi:10.1371/journal.pone.0241536PubMedGoogle Scholar
14.
Rodriguez  CA , Sasse  S , Yuengling  KA , Azzawi  S , Becerra  MC , Yuen  CM .  A systematic review of national policies for the management of persons exposed to tuberculosis.   Int J Tuberc Lung Dis. 2017;21(8):935-940. doi:10.5588/ijtld.17.0061PubMedGoogle ScholarCrossref
15.
Asghar  RJ , Patlan  DE , Miner  MC ,  et al.  Limited utility of name-based tuberculosis contact investigations among persons using illicit drugs: results of an outbreak investigation.   J Urban Health. 2009;86(5):776-780. doi:10.1007/s11524-009-9378-zPubMedGoogle ScholarCrossref
16.
Nyenswah  TG , Fallah  M , Calvert  GM ,  et al.  Cluster of Ebola virus disease, Bong and Montserrado Counties, Liberia.   Emerg Infect Dis. 2015;21(7):1253-1256. doi:10.3201/eid2107.150511PubMedGoogle ScholarCrossref
17.
Wang  W , Mathema  B , Hu  Y , Zhao  Q , Jiang  W , Xu  B .  Role of casual contacts in the recent transmission of tuberculosis in settings with high disease burden.   Clin Microbiol Infect. 2014;20(11):1140-1145. doi:10.1111/1469-0691.12726PubMedGoogle ScholarCrossref
18.
Moonan  PK , Zetola  NM , Tobias  JL ,  et al.  A neighbor-based approach to identify tuberculosis exposure, the Kopanyo Study.   Emerg Infect Dis. 2020;26(5):1010-1013. doi:10.3201/eid2605.191568PubMedGoogle ScholarCrossref
19.
Reichler  MR , Reves  R , Bur  S ,  et al; Contact Investigation Study Group.  Evaluation of investigations conducted to detect and prevent transmission of tuberculosis.   JAMA. 2002;287(8):991-995. doi:10.1001/jama.287.8.991PubMedGoogle ScholarCrossref
20.
Hogben  M , Collins  D , Hoots  B , OʼConnor  K .  Partner services in sexually transmitted disease prevention programs: a review.   Sex Transm Dis. 2016;43(2)(suppl 1):S53-S62. doi:10.1097/OLQ.0000000000000328PubMedGoogle ScholarCrossref
21.
Galloway  SE , Paul  P , MacCannell  DR ,  et al.  Emergence of SARS-CoV-2 B.1.1.7 lineage—United States, December 29, 2020-January 12, 2021.   MMWR Morb Mortal Wkly Rep. 2021;70(3):95-99. doi:10.15585/mmwr.mm7003e2PubMedGoogle ScholarCrossref
22.
Groves  R , Travis-Bassett  M , Hout  M .  Encouraging Participation and Cooperation in Contact Tracing: Lessons From Survey Research. The National Academies Press; 2020.
23.
Lash  RR , Donovan  CV , Fleischauer  AT ,  et al; Contact Tracing Assessment Team.  COVID-19 contact tracing in two counties—North Carolina, June-July 2020.   MMWR Morb Mortal Wkly Rep. 2020;69(38):1360-1363. doi:10.15585/mmwr.mm6938e3PubMedGoogle ScholarCrossref
24.
Sachdev  DD , Brosnan  HK , Reid  MJA ,  et al.  Outcomes of contact tracing in San Francisco, California—test and trace during shelter-in-place.   JAMA Intern Med. 2021;181(3):381-383. doi:10.1001/jamainternmed.2020.5670PubMedGoogle ScholarCrossref
25.
von Elm  E , Altman  DG , Egger  M , Pocock  SJ , Gøtzsche  PC , Vandenbroucke  JP ; STROBE Initiative.  The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies.   Ann Intern Med. 2007;147(8):573-577. doi:10.7326/0003-4819-147-8-200710160-00010PubMedGoogle ScholarCrossref
26.
Dong  E , Du  H , Gardner  L .  An interactive web-based dashboard to track COVID-19 in real time.   Lancet Infect Dis. 2020;20(5):533-534. doi:10.1016/S1473-3099(20)30120-1PubMedGoogle ScholarCrossref
27.
US Census Bureau. 2019 Population estimates. Published 2021. Accessed May 5, 2021. https://www.census.gov/data.html
28.
National Cancer Institute, Division of Cancer Control & Population Sciences. Joinpoint regression program, version 4.8.0.1. Published April 2020. Accessed May 5, 2021. https://surveillance.cancer.gov/joinpoint/
29.
Katul  GG , Mrad  A , Bonetti  S , Manoli  G , Parolari  AJ .  Global convergence of COVID-19 basic reproduction number and estimation from early-time SIR dynamics.   PLoS One. 2020;15(9):e0239800. doi:10.1371/journal.pone.0239800PubMedGoogle Scholar
30.
Jones  A , Fialkowski  V , Prinzing  L , Trites  J , Kelso  P , Levine  M .  Assessment of day-7 postexposure testing of asymptomatic contacts of COVID-19 patients to evaluate early release from quarantine—Vermont, May–November 2020.   MMWR Morb Mortal Wkly Rep. 2021;70(1):12-13. doi:10.15585/mmwr.mm7001a3PubMedGoogle ScholarCrossref
31.
US Centers for Disease Control and Prevention. Prioritizing COVID-19 contact tracing mathematical modeling methods and findings. Updated November 23, 2020. Accessed February 3, 2021. https://www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/prioritization/mathematicalmodeling.html
32.
Harris  G , Ong  J .  Public Health 3.0 at Mecklenburg County Public Health.   N C Med J. 2019;80(4):249-252. doi:10.18043/ncm.80.4.249PubMedGoogle Scholar
33.
McFarlane  TD , Dixon  BE , Grannis  SJ , Gibson  PJ .  Public health informatics in local and state health agencies: an update from the public health workforce interests and needs survey.   J Public Health Manag Pract. 2019;25(2)(suppl):S67-S77. doi:10.1097/PHH.0000000000000918PubMedGoogle ScholarCrossref
34.
US Centers for Disease Control and Prevention. COVID-19 contact tracing communications toolkit for health departments. Updated March 2, 2021. Accessed February 3, 2021. https://www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing-comms.html
35.
Salathé  M , Althaus  C , Anderegg  N ,  et al.  Early evidence of effectiveness of digital contact tracing for SARS-CoV-2 in Switzerland.   Swiss Med Wkly. 2020;150:w20457. doi:10.1101/2020.09.07.20189274PubMedGoogle Scholar
36.
Krueger  A , Gunn  JKL , Watson  J ,  et al.  Characteristics and outcomes of contacts of COVID-19 patients monitored using an automated symptom monitoring tool—Maine, May–June 2020.   MMWR Morb Mortal Wkly Rep. 2020;69(31):1026-1030. doi:10.15585/mmwr.mm6931e2PubMedGoogle ScholarCrossref
37.
US Centers for Disease Control and Prevention. Science brief: options to reduce quarantine for contacts of persons with SARS-CoV-2 infection using symptom monitoring and diagnostic testing. Updated December 2, 2020. Accessed February 3, 2021. https://www.cdc.gov/coronavirus/2019-ncov/more/scientific-brief-options-to-reduce-quarantine.html
38.
Young  KH , Ehman  M , Reves  R ,  et al.  Tuberculosis contact investigations—United States, 2003–2012.   MMWR Morb Mortal Wkly Rep. 2016;64(50-51):1369-1374. doi:10.15585/mmwr.mm6450a1PubMedGoogle ScholarCrossref
39.
Schuetz  AN , Hemarajata  P , Mehta  N ,  et al.  When should asymptomatic persons be tested for COVID-19?   J Clin Microbiol. 2020;59(1):e02563-20. doi:10.1128/JCM.02563-20PubMedGoogle Scholar
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