Using longitudinal genetic-network study to understand HIV treatment-as-prevention: a population-based observational study.

Objective The World Health Organization (WHO) has recommended that antiretroviral therapy be provided to all HIV patients to reduce future HIV transmission rates. However, few studies have examined this public health strategy at the population level in a real-world setting. Methods In this longitudinal genetic-network study in Guangxi, China, the baseline and follow-up data were collected from HIV patients in 2014 and newly diagnosed HIV patients from 2015 to 2018, respectively. The prevention efficacy (PE) was used to estimate the effect of treatment-as-prevention in reducing HIV secondary transmission. Results Among 804 newly diagnosed HIV patients during 2015-2018, 399 (49.6%) of them genetically linked to HIV patients at baseline during 2014-2017. The overall proportion of genetic linkage between newly diagnosed HIV patients during 2015-2018 with untreated and treated HIV patients at baseline during 2014-2017 was 6.2% and 2.9%, respectively. The PE in HIV transmission for treated HIV patients was 53.6% (95% CI: 42.1%-65.1%). Subgroup analyses indicated an 80.3% (95% CI: 74.8%-85.8%) reduction in HIV transmission among HIV patients who were treated for 4 years or more and had viral loads Conclusions Our study results support the feasibility of treating all HIV patients for future reductions in HIV transmission at the population level in real-world settings. Comprehensive intervention prevention programs are urgently needed.