Study Findings

March 2, 2020

HIV Incidence

Results from the Ya Tsie study showed a 31% decrease in the rate of new HIV infections in the intervention communities compared with the standard-of-care communities, over a total period of only 29 months.

The actual impact of the interventions was undoubtedly greater, taking into account the fact that mobility to and from the intervention communities diluted the effect of the intervention on lowering the rate of new HIV infections.Women—particularly young women—were at significantly greater risk for HIV acquisition than men, even in the intervention communities.

Kaplan-Meier Estimates of the time to seroconversion among Participants without HIV Infection and Subgroup Analysis of IHV Incidence.

Uptake of Interventions

Population levels of HIV treatment and viral suppression increased in all communities during the study period. However, significantly larger increases in coverage were observed in the intervention communities.

By study end, 88% of PLWH in the intervention communities were virally suppressed on ART. This is one of the highest population levels of viral suppression described to date and exceeds the UNAIDS target goal.

Our findings demonstrate that it is possible to further increase uptake of intervention services in a relatively short period of time in a high-prevalence generalized epidemic. Findings also suggest that sustaining high coverage ART levels over time may further reduce HIV incidence.

Knowledge of HIV Status, ART Receipt and Viral Suppression among PLWHIV by Age and Sex in 15 Intervention Communities.

Study results showed that uptake of HIV testing and treatment was not uniform across age and sex. Females of all ages were more likely to be tested, know their HIV status, and initiate treatment compared to their male counterparts.

Younger people and males had poorer ART uptake and were also less like to achieve viral suppression. However, importantly, the increases over time in viral suppression among PLWH were even greater for men than for women, and for youth as compared to older persons, in Ya Tsie. In addition, once initiated on ART, males and females perform equally well with regards to viral suppression. Our findings also provide evidence that it is indeed possible to reach men and younger persons with HIV testing and treatment interventions using more targeted and friendly approaches.

The uptake of Safe Male Circumcision during the study was low in all communities, especially in communities in the central and north of the country. By study end, 54% of eligible men in intervention communities and 42% of eligible men in standard-of-care communities reported being circumcised, an increase of 15% and 10%, respectively, from baseline levels.

Intervention Delivery

In the intervention arm, the time to ART start was significantly shorter. Community HIV testing (home-based plus mobile) and rapid ART initiation (at first clinic visit) were key to achieving this.

Rapid ART start was safe and highly acceptable to patients. Compared to traditional ART start approaches (after multiple visits and safety labs with long delays), rapid ART start resulted in much faster ART initiation and equally high retention and viral suppression rates. Active linkage to care worked well. Although most people showed up at a clinic for ART initiation at the first given appointment with a brief SMS reminder, following up on persons who did not show up led to substantial increases in timely ART start.

Approximately 15% of persons starting ART did so in a community that was not their community of residence. A data system which enabled staff to track individual patients through the care cascade, from HIV testing through clinic/ART linkage and subsequent treatment retention, was an essential element of success.

Increases in Knowledge of IHV-Positive Status from Start to End in the Intervention Communities by Age and Sex.

Additional Fundings

Risky Sexual Behaviour

The Ya Tsie study questionnaire included questions about sexual behavior, including condom use, use of alcohol during sex, number of sex partners, and multiple concurrent partners.

Among the 9,364 sexually active study participants, only 43%reported using condoms consistently (i.e. all the time) and 31% reported multiple, concurrent (or overlapping) sexual partners during the past 12 months. Employed individuals and those who consumed alcohol more than twice per week were more likely to engage in multiple concurrent partnerships. In contrast, PLWH who knew about their positive status were less likely to engage in multiple concurrent partnerships compared to undiagnosed PLWH. 

Among adolescents and young adults aged 16-24 years, females were more likely to report inconsistent condom use compared to their male counterparts. Women were also more likely to report intergenerational sexual partnerships (i.e. sexual partners aged 10 or more years older) and engage in transactional sex (i.e. exchange of sex for money or goods). However, adolescent boys and young men were more likely to engage in sex before age 15 years, consume alcohol during intercourse, and report having two or more sex partners during the past 12 months as compared to their female counterparts. 


Botswana is a mobile society. Many Batswana spend time in several locations, which may include an urban workplace, a hometown or village, a cattle post where livestock are kept, and the lands for farming.

In the Ya Tsie study, 54% of participants at baseline reported having spent at least one night away from their principal place of residence in the previous 12 months. Of those, 84% reported being in another community; 10% were at the lands, 6% were at a cattle post.

Mobile PLWH study participants were less likely to know about their positive HIV status compared to participants who stayed in the community. Similarly, even among persons aware of their HIV-positive status, mobile individuals were less likely to have started ART, and less likely to have a suppressed HIV viral load as compared to PLWH who were not mobile. When compared with non-mobile participants, mobile individuals had more concurrent partners and were more likely to have changed partners over the past 12 months. 


Among study participants, 68% reported having a religious affiliation. When comparing religious affiliated with those not affiliated, data showed that the religious affiliated were more likely to be aware of their HIV status (85% vs 79%), to be on ART (75% vs 68%), and to be virologically suppressed (97% vs 94%). In Botswana, religious affiliation seems to confer a positive effect on an individual’s health.

Transmission Networks

The high mobility of Botswana’s population may partly explain why Botswana has such a high HIV prevalence. In the illustration above, different coloured lines show the link between virus found in one study community being genetically related to virus found in another community. 

By sequencing the genomes of HIV collected from the Ya Tsie study, researchers can learn more about the evolutionary history and transmission dynamics of HIV, which will provide a better understanding of how HIV travels in and between communities. Work on this topic is ongoing.

HIV-1C Transmission Networks in Botswana