The population impacts of ART scale-up in rural KwaZulu-Natal, South Africa: Results from the Africa Centre s population cohort

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1 The population impacts of ART scale-up in rural KwaZulu-Natal, South Africa: Results from the Africa Centre s population cohort Frank Tanser Presentation at 8 th International Workshop on HIV Treatment, Pathogenesis and Prevention Research in Resource-Poor Settings, Lusaka 6 th May 2014

2 Outline Background ART coverage and risk of HIV acquisition Population viral load

3 Global ART scale-up South Africa has the worldwide largest absolute number of patients on ART, >1.6 million by some estimates UNAIDS Report on the Global AIDS Epidemic 2012; WHO Universal Access Report 2013; Aaron Motsoaledi 2012

4 Study setting Adult HIV prevalence 24% High levels of unemployment and poverty Zulu-speaking population Former homeland under apartheid

5 The Africa Centre Africa Centre for Health and Population Studies

6 Adult life expectancy over time 13,060 deaths among 101,286 individuals aged 15 years and older, contributing a total of 651,350 personyears of followup time Bor, Herbst, Newell, and Bärnighausen Science 2013

7 HIV incidence by age and sex Females 0.1 Males HIV Incidence (per Year) HIV Incidence (per year) Age (Years) Age (years) Tanser, Bärnighausen, Newell CROI 2011

8 Spatial clustering of new HIV infections Tanser et al CROI. Boston, MA; 2011.

9 Outline Background ART coverage and risk of HIV acquisition Population viral load

10 Population-based HIV surveillance Since 2003: Population-based HIV cohort Longitudinal, dynamic cohort Entire adult population living in a contiguous geographical area of 438 km 2 eligible for testing Annual rounds 75% of those observed to be HIVuninfected subsequently retest All individuals geo-located Tanser, Hosegood, Bärnighausen et al. International Journal of Epidemiology 2007

11 ART coverage of all HIV-infected individuals Tanser, Bärnighausen, Grapsa, Zaidi & Newell Science 2013

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13 Population impact of ART coverage on risk of HIV acquisition ( ) Survival analysis Adjusted Hazard ratio 1,2 1 0,8 0,6 0,4 0,2 0 p=0.171 P< p< P< <10% 10-20% 20-30% 30-40% 40-50% >50% Proportion of all HIV positive people receiving ART p=0.004 > 17,000 HIVnegative individuals followed-up for HIV acquisition over 60,558 person-years 1,573 HIV seroconversions Adjusted for age, sex, community-level HIV prevalence, urban vs. rural locale, marital status, >1 partner in last 12 months, and household wealth index Time- (and space-) varying demographic, sexual behavior, economic and geographic controls, including HIV prevalence

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15 Conclusion We find continued reductions in risk of acquiring HIV infection with increasing ART coverage in this typical rural sub- Saharan African setting However, there is suggestion of a reduction saturation effect (at coverage of >40%) under treatment guidelines of <350 CD4 + cells/µl

16 Outline Background ART coverage and risk of HIV acquisition Population viral load

17 Population/Community viral load Proposed as: an aggregate measure of the potential for ongoing HIV transmission within a community as a surveillance measure for monitoring uptake and effectiveness of antiretroviral therapy.

18 Figure 1 CVL as a measure for assessment of HIV treatment as prevention Miller, Powers, Smith et al Lancet Infectious Diseases 2013

19 CVL as a measure for assessment of HIV treatment as prevention The issue of selection bias [in community viral load] could be addressed with a population-based survey in a clearly defined target population of all people in a community, including those with and without known HIV infection Miller, Powers, Smith et al Lancet Infectious Diseases 2013

20 Objectives 1. Asses whether viral loads in this population are randomly distributed in space or whether high or low viral loads tend to cluster in certain areas 2. Assess the degree to which different population viral load summary measures highlight known areas of high incidence 3. (Establish the degree to which different population viral load summary measures predict future risk of new HIV infection in uninfected individuals)

21 Methods All 2,456 individuals testing positive in the population-based HIV testing conducted in 2011 Total number DBS specimens tested was 2,420 (36 specimens excluded due to being insufficient for testing). Of these, 30% (726) were below the detectable limit of 1550 copies/ml (Viljoen et al, JAIDS 2010)

22 Viral load distribution Density 0 1.0e e e-06 Median viral load = 6428 copies per ml VL Result (copies/ml)

23 Geometric mean population viral load Copies /ml

24 Prevalence of unsuppressed viral load Prevalence (%)

25 Population prevalence of detectable virus (PPDV) Prevalence(%)

26 Conclusion To measure transmission potential of a community, any viral load summary index must take into account the size of the uninfected population Population prevalence of detectable virus (PPDV) successfully identified known areas of continued high HIV incidence We propose the PPDV as a simple community-level index of transmission potential

27 Acknowledgements The members of the community in Hlabisa sub-district who gave their time to this research Staff of the Africa Centre for Health and Population Studies and the Hlabisa HIV Care and Treatment Programme Colleagues at Africa Centre (Marie-Louise Newell, Till Bärnighausen, Tulio de Oliveira,Kobus Herbst, Colin Newell, Jacob Bor, Jaffer Zaidi and many more) Funding Wellcome Trust (Africa Centre for Health and Population Studies) National Institutes of Health grants R01 HD and 1R01MH