Prospective Case-control Study of Contact Tracing Speed for Emergency Department-based Contact Tracers.

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Emergency Medicine

Background:

• Contact tracing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Snohomish County, WA, experienced delays of 4-6 days between positive testing and initiation.
• Existing contact tracing protocols faced challenges in timely completion and case identification.

Purpose of the Study:

• To evaluate the effectiveness of emergency department (ED)-based contact tracing in reducing the time to initiation and completion of investigations.
• To compare ED-based contact tracing outcomes with standard public health department (SHD) practices.

Main Methods:

• A prospective case-control study enrolled eligible coronavirus disease 2019 (COVID-19)-positive patients.
• Contact tracers were stationed in the ED for 60 days, interviewing patients using the state's reporting form.
• Data collected included time to initiation and completion of tracing, enrollment rates, and number of contacts identified.

Main Results:

• The mean time to initiate ED-based contact tracing was 111 minutes (median 32), significantly faster than standard methods.
• Contact tracing was completed within 24 hours for 100% of ED-enrolled cases, compared to 64% for SHD cases (P < 0.001).
• ED-based tracing identified an average of 2.8 contacts per case, versus 1.4 for SHD cases, with similar contact reach rates (82% vs. 78%).

Conclusions:

• Implementing contact tracing at the point of diagnosis in the ED substantially improves timeliness.
• ED-based contact tracing leads to higher patient enrollment and identification of more contacts.
• This model offers a more efficient strategy for managing infectious disease outbreaks.