Population-based impact of ART in high HIV prevalence

settings

Marie-Louise NewellProfessor of Global Health

Faculty of Medicine, Faculty of Social and Human Sciences, University of Southampton

USRG Population Health Summer Conference June 2014

Total: 35.3 million (32.2 – 38.8 million)

Western & Central Europe860 000860 000

[800 000 – 930 000][800 000 – 930 000]Middle East & North Africa

260 000260 000[200 000 – 380 000][200 000 – 380 000]

Sub-Saharan Africa

25.0 million25.0 million[23.5 – 26.6 million][23.5 – 26.6 million]

Eastern Europe

& Central Asia1.3 million 1.3 million [1.0 – 1.7 million][1.0 – 1.7 million]

South & South-East Asia

3.9 million3.9 million[2.9 – 5.2 million][2.9 – 5.2 million]Oceania

51 00051 000[43 000 – 59 000][43 000 – 59 000]

North America1.3 million

[980 000 – 1.9 million]

Latin America1.5 million1.5 million

[1.2 – 1.9 million][1.2 – 1.9 million]

East Asia880 000880 000

[650 000 – 1.2 million][650 000 – 1.2 million]Caribbean250 000

[220 000 – 280 000]

Estimated number of Adults and Children living with HIV by region, 2012

Source: UNAIDS 2013 report

New infections and AIDS deaths 2012

Estimated number of people newly infected with HIV:

Estimated number of AIDS deaths:

Total 2.3m (1.9m-2.7m)

Adults 2.0m (1.7m-2.4m)

Children < 15 years

260,000 (230,000-320,000)

Total 1.6m (1.4m-1.9m)

Adults 1.4m (1.2m-1.7m)

Children < 15 years

210,000 (190,000-250,000)

Source: UNAIDS 2013

About 2/3 of all people with HIV globally reside in sub-Saharan Africa

Global antiretroviral treatment (ART) programme scale-up

• In 2012 there were nearly 10m HIV infected people on ART globally, of whom 7.5 million (~ 25% of the estimated HIV infected population) in sub-Saharan Africa

• 1.6m more people were receiving ART in low- and middle-income countries in 2012 than in 2011, most of this increase came from sub-Saharan Africa

• South Africa has the largest absolute number of HIV infected people, ~6.4m, worldwide and the largest number on ART at > 2m in 2012

Africa Centre, KwaZulu-Natal

HIV prevalence,ART coverage, and HIV

incidence in the population

Africa Centre surveillance area HIV prevalence 2004-2011

• In 2011, overall HIV prevalence among adults ≥ 15 years of age was 24%

• Among 15-49 year residents, prevalence increased from 21% in 2004 to 29% in 2011;

• ART coverage of HIV infected people in this age group increased from 0% in 2004 to nearly 31% in 2011

Zaidi et al, AIDS 2013

Females

Males

Red HIV prevalence; Blue ART coverage

HIV incidence by age and sex, 2004-2011, residents in Africa

Centre surveillance area

Females Males

HIV incidence overall about 3%; peaking at 7% at age 24 for women and nearly 5% in men at age 29

Tanser, Bärnighausen, Grapsa, Zaidi & Newell, Science 2013

HIV incidence and ART coverage

ART coverage

2004-112004-2011

*Using a standard Gaussian kernel of radius 3km

• ART coverage = proportion of the total HIV-infected population receiving ART

• Patients on treatment: Individual, geo-located DOH programme adult patients actively on treatment in June (2004-2011)

• HIV-infected: Individual, geo-located, HIV positive adults identified through population-based HIV surveillance data (2004-2011)

Adjusted HIV acquisition hazard by ART coverage category

Adjusted for age, sex, community-level HIV prevalence, urban vs. rural locale, marital status, >1 partner in last 12 months, and household wealth index Tanser et al, Science, 2013

Mother-to-child transmission

• Identification of HIV in early pregnancy

• ART from the 2nd trimester of pregnancy, during delivery and breastfeeding

• Substantial and significant reduction of MTCT rates, from about 15% to <2% at 6 weeks and 30% to <4% at 18 months

Impact of ART programme on child and adult mortality

Mortality (deaths

per 10,000 pyo) in the

0-4 year age group; 2000-2009

Child mortality and association with PMTCT and

ART roll-out• Under- 2 child mortality rates in the surveillance

area declined substantially from 2001: – sdNVP PMTCT availability associated with a non-

significant 15% decrease, – ART roll-out associated with a 34%-55% reduction

(depending on estimated coverage in setting) (Ndirangu et al AIDS 2010, 24: 593-602)

• Subsequently, with linked ART data, we showed that under-5 mortality in children of HIV infected mothers on ART and those born to uninfected mothers did not differ significantly

(Ndirangu et al, Antiviral Therapy 2012; 17: 81-90)  

Mortality in adults 2000-2009, deaths per 10,000 PYO

15-49 yr Age Standardised 50-64 yr Age Standardised

Herbst et al; Population Health Metrics 2011

60.5 years

in 2011

60.5 years

in 2011

49.2 years in 2003

Mortality reductions lead to major gains in life expectancy

Bor, et al. Science 2013; 339: 961-965

Employment recovery

following ART initiation

Bor, Tanser, Newell, Bärnighausen Health Affairs 2012

In this high unemployment area, the likelihood of being in employment further decreases with HIV disease progression. However, within 3-4 years following ART initiation employment likelihood is back to ‘normal’ levels

Aging of the population Aging of the population as HIV infected people on treatment live longer, with continued low level HIV incidence in the over-50s:

– HIV prevalence in people aged over 50 years will nearly double by 2040

– The fraction of HIV-infected people over 50 years will triple in the same period

– in 2011 about 1:7 HIV infected people were 50 years or older, in 2040 this will be 1:4

Hontelez et al, AIDS 2011; 25(13): 1665-7 Walker et al Lancet Global Health 2013; 1: e282-288

Elimination of the HIV epidemic?

• Results from a trial of ART in discordant couples have strengthened the arguments for Treatment-as-Prevention, with statistical models suggesting possible elimination of HIV from the population (Cohen et al NEJM 2011; 365: 493-505)

• Recent models suggest that high ART coverage at CD4 <350 cells/µl together with male medical circumcision would be most cost-effective in reducing transmission and mortality (Bärnighausen, Bloom and Humair, PNAS 2012; 109: 21271-76)

• High ART coverage at eligibility of CD4 < 350 cells/µl is modelled to virtually eliminate HIV albeit up to 10 years later than universal ART would (Hontelez et al. PLoS Med 2013)

Conclusion• HIV continues to be a major public health

challenge in sub-Saharan Africa • Impressive increase in number of HIV infected

people on treatment• Substantial reduction in new infections is

possible • Mother-to-Child transmission can be ‘virtually’

eliminated• Sexual transmission can be reduced significantly• Reduction in HIV-related mortality and

consequent aging of the population will necessitate refocussing of health care programmes

Syabonga