Analysis of HIV contact tracing in Yunnan Province: data-driven insights for optimizing HIV prevention and control strategies

Background: To effectively control the spread of HIV, this study evaluated contact tracing implementation among newly diagnosed individuals in Yunnan Province, China-a region heavily affected by HIV. Methods: From January to June 2020, contact tracing targeted newly diagnosed HIV cases to identify sexual/drug-injecting partners. Factors correlated with index cases, close contacts, and positive testing outcomes were analyzed. Results: Among 5,695 new HIV cases, 1,612 (28.3%) received tracing counseling, revealing 2,226 close contacts. Of the 1,612 index cases, 182 were recently infected, while 1,430 had been infected long-term. Of the 2,226 close contacts, 910 underwent HIV antibody testing, with 17.8% (162/910) testing positive. Notably, 132 of these contacts were newly diagnosed with HIV, representing 14.5% of those tested. The detection rates for both positive and newly diagnosed infections were higher among contacts identified by recently infected index cases than among those identified by long-term infected index cases. A multivariate analysis showed that HIV index cases of other ethnicities (adjusted odds ratio (aOR) = 1.688, 95% confidence interval (CI): 1.495-1.905), the divorced (aOR = 1.430, 95%CI: 1.237-1.654), those traced through voluntary counselling and testing (VCT) (aOR = 1.707, 95%CI: 1.077-2.705) and those exposed to commercial sex (aOR = 1.437, 95%CI: 1.257-1.642) were more likely to receive tracing counselling. Among close contacts, those who were Han Chinese (aOR = 1.231, 95% CI: 1.012~1.498), married (aOR = 1.738, 95% CI: 1.339 ~ 2.255), had a high school education or higher (aOR = 2.809, 95% CI: 1.849~4.267) or were exposed to positive spouses or regular sex partners (aOR = 2.403, 95% CI: 1.741~3.317) were more likely to undergo HIV testing. A higher positive testing rate was observed among men (aOR = 2.608, 95% CI: 1.740~3.911), ethnic minorities (aOR = 1.645, 95% CI: 1.098~2.465), individuals aged 40-49 (aOR = 2.733, 95% CI: 1.497~4.990) and individuals exposed to positive spouses or regular partners (aOR = 2.215, 95% CI: 1.411~3.477). Conclusion: HIV recent infection testing is instrumental in enhancing the efficiency of contact tracing efforts. The variability in contact tracing uptake among diverse populations underscores the necessity for tailored strategies. These findings provide strong support for optimizing HIV prevention and control strategies, facilitating more precise disease management objectives.