Delivering Partner Services to Reduce Transmission and Promote Linkage to Care: Process Outcomes Varied for Chlamydial Infection, Gonorrhea, HIV, and Syphilis Cases

CONTEXT

Partner services for HIV and sexually transmitted diseases, a public health intervention activity recommended by the Centers for Disease Control and Prevention, includes counseling, partner notification, linkage to care, and referral to other services.

OBJECTIVE

A time study of partner services case investigations documented differences in times to process HIV/sexually transmitted disease cases.

SETTING

Cases were from 9 local and regional sites in New York.

PARTICIPANTS

Fifty-two partner services disease investigators documented 542 randomly selected cases (271 chlamydial infections, 162 gonorrhea, 48 HIV, and 61 syphilis cases) assigned between June and September 2014. Cases were the unit of the analysis and represented 6.9% of all partner services investigations in 2014.

DESIGN

Cases were selected via stratified random sampling of infections assigned to staff. For each case, disease investigators completed a standard time study form to document the time spent on specific tasks and other outcomes. Kruskal-Wallis tests for continuous variables and χ tests for categorical variables assessed variation in outcomes across infection type.

MAIN OUTCOME MEASURES

Outcomes included minutes spent on specific tasks (such as medical provider and index case outreach, travel, and partner notification), days the case remained open, disposition codes, and number of partners reached.

RESULTS

Case processing times varied, with HIV and syphilis tasks taking more minutes (P < .001) and cases staying open for more days (P < .001). Partners were notified in 33% of cases overall, with more notifications in syphilis (44%). Most time (median = 77%) was spent on index cases and 2% (median) on partner notification, with a wide range across cases.

CONCLUSIONS

Given their chronic resource constraints, public health agencies must identify efficient methods to allocate resources, including which infections to prioritize. Documenting how workers allocate time across cases is essential to improving the effectiveness and efficiency of this program and generating the data to model return on investment.

Individual and population level effects of partner notification for Chlamydia trachomatis

Partner notification (PN or contact tracing) is an important aspect of treating bacterial sexually transmitted infections (STIs), such as Chlamydia trachomatis. It facilitates the identification of new infected cases that can be treated through individual case management. PN also acts indirectly by limiting onward transmission in the general population. However, the impact of PN, both at the level of individuals and the population, remains unclear. Since it is difficult to study the effects of PN empirically, mathematical and computational models are useful tools for investigating its potential as a public health intervention. To this end, we developed an individual-based modeling framework called Rstisim. It allows the implementation of different models of STI transmission with various levels of complexity and the reconstruction of the complete dynamic sexual partnership network over any time period. A key feature of this framework is that we can trace an individual's partnership history in detail and investigate the outcome of different PN strategies for C. trachomatis. For individual case management, the results suggest that notifying three or more partners from the preceding 18 months yields substantial numbers of new cases. In contrast, the successful treatment of current partners is most important for preventing re-infection of index cases and reducing further transmission of C. trachomatis at the population level. The findings of this study demonstrate the difference between individual and population level outcomes of public health interventions for STIs.