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Why is HIV Prevalence So Severe in Southern Africa?, and “What Works” (and Doesn’t) for AIDS Prevention? Daniel Halperin, PhD, MS Senior Advisor for Behavior.

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Presentation on theme: "Why is HIV Prevalence So Severe in Southern Africa?, and “What Works” (and Doesn’t) for AIDS Prevention? Daniel Halperin, PhD, MS Senior Advisor for Behavior."— Presentation transcript:

1 Why is HIV Prevalence So Severe in Southern Africa?, and “What Works” (and Doesn’t) for AIDS Prevention? Daniel Halperin, PhD, MS Senior Advisor for Behavior Change/Primary Prevention, USAID With assistance from colleagues at USAID, World Bank, Global Fund, UCSF, etc.

2 Key Points * Back to the Basics: using a “basic public health” approach to prevention Using evidence (vs. politics, ideology, etc.) to set priorities *Prevention works (Uganda today compared to yrs. ago) [Please see the “notes” under most of the slides!]

3 HIV PREVALENCE BY REGION Source: Adapted from WHO AFRO 2003 Report Southern Africa Eastern Africa Central Africa West Africa % HIV prevalence 2004 Report on the Global AIDS Epidemic (Fig 8)

4 TRANSMISSION DYNAMICS  Epidemic concentrated - if transmission occurs largely among vulnerable groups and vulnerable group interventions would reduce overall infection  Epidemic generalized - if transmission occurs primarily outside vulnerable groups and would continue despite effective vulnerable group interventions  Epidemics DON’T inevitably keep escalating

5 HIV TRANSMISSION PATTERNS IN ACCRA, GHANA, 2003 Sources: GAC/NAP and Cote et al data, 2004

6 HIV TRANSMISSION PATTERNS IN MASHONALAND CENTRAL, ZIMBABWE Sources: Wilson and Cowan et al data, 2003

7 Economic Status and HIV prevalence (Tanzania) Source: AIS

8 Education Status and HIV prevalence in Tanzania Source: AISS

9 Why is HIV so much Higher in Southern Africa?? Multiple concurrent partnerships (“nyatsi,” “lishende,” “small house,” “second office”...) Lack of male circumcision And various other factors, such as relatively developed/highly mobile societies, income inequality, gender dynamics, "dry sex,” etc.

10 Source: 2002 Lesotho BSS

11

12 “Concurrent” Partnerships * Source M. Carael, 1995; Halperin and Epstein, 2004

13 “Concurrent” Partnerships * Source M. Carael, 1995; Halperin and Epstein, 2004

14 Proportion of year-olds reporting more than one current sexual partner, South Africa 2005 Source: South African National HIV Prevalence, HIV Incidence, Behavior and Communication Survey, 2005

15 “ Map” of the largest component of a sexual network in Likoma, Malawi Source: Kohler H and Helleringer S. The Structure of Sexual Networks and the Spread of HIV in Sub-Saharan Africa: Evidence from Likoma Island (Malawi). PARC Working Paper Series: WPS 06-02

16 A NATION AT WAR WITH HIV&AIDS Low degree networks create a transmission core In largest component: 2% 41% 64% 10% Mean: 1.74 Mean: 1.80 Mean: 1.86 Largest components Mean: 1.68 Number of Partners Bicomponents in red Source: Martina Morris, Univ. of Washington, used with permission from a presentation given at a meeting on concurrent sexual partnerships and sexually transmitted infections at Princeton University, 6 May 2006.

17 Transmission efficiency “Mathematical models estimate the average probability of male–female transmission of HIV-1 per unprotected coital act to be between and 0.003% during chronic HIV infection, which in itself would not sustain an epidemic.” -Pao et al, AIDS (2005)

18 “Acute Infection” and Concurrence

19 Source: WHO/GPA surveys BEHAVIOURAL AND HIV TRENDS IN UGANDA

20 CONCLUSION MCP is a driver Behavior can be changed Challenge – HOW Social Movement


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