Completeness and timeliness of a contact tracing intervention during the COVID-19 pandemic: an outcome evaluation of the California Contact Tracing Support Initiative

Abstract Objectives To describe COVID-19 case investigation and contact tracing outcomes from an intervention conducted in two California counties under the California Contact Tracing Support Initiative (CCTSI). Methods We analyzed contact tracing program metrics in two counties using de-identified individual-level records from COVID-19 cases and their contacts. Interviews with 47 program staff were conducted and analyzed using thematic analysis. Results In one county, 64% of assigned COVID-19 cases (2,722 of 4,279) were successfully interviewed, with 77% (2,105) of interviews occurring within 48 hours of receiving test results; 63% of assigned contacts (418 of 660) were notified, with 82% (348) of notifications occurring within 48 hours of contact elicitation. In a second county, 52% of cases (1,743 of 3,352) were interviewed, with 48% (1,621) interviewed occurring within 48 hours; 79% of contacts (155 of 196) were notified, with 82% (127) notified within 48 hours. CCTSI staff reported faster receipt of test results in the early months and positive perceptions of wrap-around service referrals. Conclusions The performance of the CCTSI contact tracing intervention differed across two California counties. In both counties, there was moderate to high case interview completion and contact notification overall and within 48 hours of case and contact identification, but relatively few contacts were elicited per case. The perceived benefit of several program features was high among staff and stakeholders. The evaluation highlighted generalizable challenges in contact tracing investigations and linking contact and case records in contact tracing databases.