A Social Network Analysis of Contact Tracing Data Reveals Strategies to Improve Contact Tracing Protocols

Background:  Contact tracing is a core component of most STD programs in the US. It results in a large amount of data on sexual networks that is stored within STD surveillance databases, but is typically not fully utilized. Supplementing our traditional focus on individuals and their behavior, the Florida STD Program conducted an exploratory social network analysis (SNA) of a subset of contact tracing data. This was done in order to ascertain what could be learned by using a network lens. This information can be used to point to potentially more effective contact tracing protocols in STD prevention efforts.

Methods:  Contact tracing data obtained from two syphilis cases revealed a sexual network of 139 men who have sex with men (MSM). Routinely collected surveillance data were utilized, including demographics, current and previous STD diagnosis (chlamydia, gonorrhea, syphilis and HIV), and MSM status. Networks were visualized using SNA software.

Results:  Of the 139 men, 29 (21%) were designated as MSM and 20 (14%) were positive for an STD during the current investigation. Considering only those we were able to test  during the investigation (n=73), 27% were positive. 27 (19%) had at least one diagnosis of an STD in our database prior to the current investigation.  Despite the high-risk nature of these networks, only 12 (9%) received contact tracing interviews during the current investigation.

Conclusions:  Visualizations of the networks highlighted three important findings: 1) the number of MSM at risk for STDs in Florida may be under-estimated due to the reliance on interview data to determine MSM status, 2) contact tracing protocols may need to take into consideration past positivity and network characteristics in determining who should be interviewed, and 3) contact tracing activities by local STD programs potentially provide a wealth of data on high-risk networks otherwise difficult to obtain.