Combining Social, Behavioral & Biomedical

The drivers of the epidemic

Source: UNAIDS (2010) Report

Combining Social, Behavioral & Biomedical Science in Prevention of HIV

Noah Kiwanuka, MD,PhD Makerere University College of Health Sciences School of Public Health

Prevention: an urgent global priority  Despite declining HIV incidence globally, for every individual started on ART, 2 new HIV infections occur. Thus strengthening HIV prevention remains an urgent global health priority (UNIADS report, 2010)  To-date, a number of HIV prevention interventions can significantly reduce new infections with varying degrees of efficacy (31 – 96%).  These include among others: Biomedical -

ART for infected (PEP and Rx for prevention), ART for uninfected but exposed persons (PREP, microbicides) Safe male circumcision Prevention of mother-to-child transmission

Socio-behavioral - Consistent condom use, - HIV testing and counseling, behavioral change,

Combination prevention • Since none of these interventions can singly eliminate HIV, it is plausible that when used in combination with each other, they can dramatically reduce or possibly eliminate new HIV infections. • UNAIDS (2010) definition of combination HIV prevention “The strategic, simultaneous use of different classes of prevention activities (biomedical, behavioral, social/structural) that operate on multiple levels (individual, relationship, community, societal), to respond to the specific needs of particular audiences and modes of HIV transmission, and to make efficient use of resources through prioritizing, partnership, and engagement of affected communities”

Combination prevention- 2 – Evidence informed strategic, and simultaneous use of different complementary behavioral, biomedical and structural interventions – to address both the immediate risks and underlying causes of vulnerability to HIV infection, and the pathways that link them, – so as to generate significant and sustained reductions in HIV incidence in diverse settings. [Hankins CA, and de Zalduondo BO, AIDS. 2010 Oct;24 Suppl 4:S70-80].

Role of different disciplines to HIV combination prevention science

Epidemiology • Identify key populations at risk – CSWs, Fisher folk, MSM, IDUs

• Determine risk factors and magnitude of risk – Prevalence, incidence, attributable risk

• Evaluation of impact of interventions – single or combination – Efficacy – Effectiveness (individual and population)

Social Sciences • Identify and determine characteristics of risk behaviors and change/modification – Sexual networks and mixing

• Understand modes of and reasons for various risky behaviors – Multiple partners, unprotected sex, unfaithfulness

• Understand issues of demand generation for combination prevention – High risk folks not coming for SMC, why? – Eligible persons coming late for ART – Poor adherence to ART

Basic Sciences • Biology of HIV and immune response to infection – What HIV is, how is infect human cells, and its interaction with the immune system, and causes disease, – Different types and subtypes and their implication to natural history – Why host immune response doe not fully control HIV infection? – How reservoirs of infection persist in body despite HAART? – Correlates of immune protection etc

• Biological basis of risk, infection, and protection – Biological endpoints and biomarkers • infection, progression, response – correlates of risk and protection

Ideal combination prevention package (s) • Evidence-based, • Complementary, • Feasible / appropriate,

• Applicable /deliverable (high level of coverage) • Acceptable (with high adherence), • Efficacious and effective (individual & population) • Cost-effective • Sustainable

Challenges  Which of proven individual interventions can be combined?

 Criteria for inclusion of an intervention in a prevention “package?” – – – – –

Magnitude of impact Nature of studies adducing evidence? RCTs, observational Number of studies (in various population settings) Consistency of results Examples • High impact on HIV incidence, multiple RCTs—PMTCT , MMC, • High impact on HIV incidence, single RCT—PREP HPTN052. • Moderate impact – Microbicides CAPRISSA 004 , iPREX, • Evidence based on preliminary data, observational data, plausibility of intervention ( faithfulness, consistent condoms use, STI Rx, preventive HIV vaccine.

Challenges - 2  No evidence yet on efficacy/effectiveness of combination prevention – current evidence based mainly on single interventions – On-going studies in Botswana, South Africa

 Interventions found to be efficacious in one setting may not necessarily be replicable in other settings and may require cultural adaptation.  Impact of combination prevention on health systems and nonHIV services

Challenges -3 • Sexual networks and intra- and intercommunity transmission. Rakai, spatial clustering statistics, phylogenetic analyses, and probabilistic transmission models - 43% of transmissions occur within stable household partnerships, - Of those who acquire HIV infection from extra-household sexual contacts are more often infected by partners from outside (63%) than from within their community (37%).

What are the implications on locally targeted “test and treat”