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Scientific Approaches to Program Components: Opportunities Challenges and Impact. Sevgi Aral, PhD. Istanbul, Turkey March 21, 2011. National Center for HIV/AIDS, Viral Hepatitis, STD , and TB Prevention. Why now? So many efficacious STI/HIV interventions – so little impact.

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scientific approaches to program components opportunities challenges and impact
Scientific Approaches to Program Components: Opportunities Challenges and Impact

Sevgi Aral, PhD

Istanbul, Turkey

March 21, 2011

National Center for HIV/AIDS, Viral Hepatitis, STD , and TB Prevention

slide2

Why now?

  • So many efficacious STI/HIV interventions – so little impact
slide3

Goal: To prevent individual acquisition

To prevent individual transmission

To reduce population incidence

efficacious individual intervention
Efficacious Individual Intervention

distribution of technology

dissemination of knowledge

cost

affordability

side-effects

Access/ acceptability

correct use

consistent use

correct timing

correct dose

long-term maintenance of above

Adherence

changes in risk perception

↑ other risk behaviors

Disinhibition

(risk compensation)

Successful Prevention

Of Individual Acquisition/Transmission

successful prevention of individual acquisition transmission
Successful Preventionof Individual Acquisition/Transmission

Identification

affected subpopulations

sexual structures

social practices; demographic patterns; migration & turnover

organizational structures

epidemic phase/epidemic trajectory

identified need

organizational capacity/financial resources

synergies and antagonisms among interventions

context XX intervention interactions

Intervention Mix

  • sexual mixing patterns → who are exposed to pathogen
      • who are transmitting pathogen
  • sexual networks → which are central positions and roles

Prevention targets

numbers and social location of persons to prevent acquisition/

transmission

pathways for introduction and scale-up of interventions

Coverage & scale-up

subpopulations

sexual structures

sexual behaviors

intervention implementation

POPULATION (SUBPOPULATION) INCIDENCE

M & E

Reduction of Population

Incidence

slide7

B

  • B
  • B

C

D

E

  • A
  • B
  • A
  • B
  • B
  • B

Not only at individual level

bridge populations

men

slide8

Often it seems

Prevention of acquisition and transmission (in individuals) framework is used when thinking about reducing population incidence

?? Is the hidden individualistic biomedical (psychological) model the culprit???

opportunities
Opportunities

Huge we are not doing an adequate job of: identification; determining intervention mix; determining prevention targets; coverage and scale-up issues; monitoring and evaluation (of population impact)

assessing the relationships among these

assessing the interactions

between context and intervention schemes

how well do we assess the context
How well do we assess the context?

Epidemiology

distribution and concentration of infection

emergent clusters

geographic distribution

sexual structures → where the epidemic is going?

epidemic trajectory

epidemic phase

Socio-demographic context

behavior patterns

sexual mixing patterns

migration

turnover in key populations

key populations – powerful men, police, military

slide11

Perhaps we do not examine epidemiology sufficiently

(or we do not respect what we observe sufficiently)

slide12

Paper # 137Identification of Localized Clusters of High HIV Incidence in a Widely Disseminated Rural South African Epidemic: A Case for Targeted Intervention Strategies

Frank Tanser*1, T Bärnighausen1,2, and M-L Newell1,3

1Africa Ctr for Hlth and Population Studies, Univ of KwaZulu-Natal, Durban, South Africa; 2Harvard Sch of PublHlth, Boston, MA, US; and 3Inst of Child Hlth, UnivColl London, UK

Session 38-Oral Abstracts

http://www.retroconference.org/2011/Abstracts/41395.htm

slide13

Paper # 137Identification of Localized Clusters of High HIV Incidence in a Widely Disseminated Rural South African Epidemic: A Case for Targeted Intervention Strategies

Conclusions:  Targeting efforts at settings where HIV

transmission is most intense is crucial. Our study

provides clear empirical evidence for the localized

clustering of new HIV infections. The results show that

even in a severely affected rural African community,

interventions that specifically target, geographically

defined, high-risk communities could be highly

effective in reducing the overall rate of new infections.

Session 38-Oral Abstracts

http://www.retroconference.org/2011/Abstracts/41395.htm

hiv incidence across the study area with high incidence clusters superimposed
HIV incidence across the study area with high-incidence clusters superimposed

Session 38-Oral Abstracts

http://www.retroconference.org/2011/Abstracts/41395.htm

slide16

….and it is not only infections that cluster geographically….

In the Bagalkot district of Karnataka in South India

15 % of the villages accounted for 54% of all rural FSW

Blanchard JF et al. Sex Transm Infect 2007; 83:i30-i36 d oi:10.1136/sti.2006.023572

slide17

In the UK…Project SIGMA found “….Most individuals (60%) who engage in AI do so only once or twice a month, but there is a long tail of those who do it much more. In terms of the amount of AI acts, one-tenth of the individuals are performing half of the acts of AI. The Gini coefficient of concentration is high (0.55).”

Coxon PM and McManus TS. The Journal of Sex Research 2000

in the u s
In the U.S.

20% of women

account for

60% of vaginal sex acts in past 4 weeks

and

24% of men

account for

61% of vaginal sex acts in past 4 weeks

Leichliter JS et al. Sex Transm Infect December 2010; 86(Suppl 3):

in the u s1
In the U.S.

20% of women

account for

47% of opposite sex partners in past year

and

20% of men

account for

57% of opposite sex partners in the past year

Leichliter JS et al. Sex Transm Infect December2010; 86(Suppl 3)

in the u s county level analysis
In the U.S. (county level analysis)

20% of the population

accounts for

39% of Chlamydia

52% of Gonorrhea

64% of Primary and Secondary Syphilis

Chesson HW et al. Sex Transm Infect December 2010; 86(Suppl 3)

slide21

Perhaps we do not assess “context” sufficiently

(or we do not respect the context we observe adequately)

aral so partner concurrency and the std hiv epidemic curr infect dis rep 2010 12 2 134 139
Aral SO.  Partner concurrency and the STD/HIV Epidemic.  Curr Infect Dis Rep 2010; 12(2):134-139.
slide24
Concurrency is more complex than it seemsMirjam Kretzschmar,1,2 Richard G. White,3 and Michel Caraël4

1Centre for Infectious Disease Control, RIVM, Bilthoven, The Netherlands

2Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, The Netherlands

3Infectious Disease Epidemiology Unit, Department of Epidemiology and Population Health and Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, UK

4Department of Social Sciences, Free University of Brussels, Belgium

Corresponding Author: Dr MirjamKretzschmar, Corresponding Author’s Institution: University of Bielefeld

Keywords: Polygyny, concurrency, HIV transmission

Published in final edited form as: AIDS. 2010 January 16; 24(2): 313–315.

doi: 10.1097/QAD.0b013e328333eb9d.

slide25
Concurrency is more complex than it seemsMirjam Kretzschmar,1,2 Richard G. White,3 and Michel Caraël4

However, the empirical basis proving that concurrency actually is the

driving force behind the continuing high prevalence of HIV in sub

Saharan Africa has been lacking. While some studies investigated the

impact of concurrent partnerships on the prevalence of HIV in various

sub-Saharan Africa populations [7-9], they were not able to identify

concurrency as a strong explanatory factor. Also, epidemiological

observations like the decrease of HIV prevalence in Uganda following

the advocacy of the “zero grazing” strategy for HIV prevention [10, 11]

is not conclusive evidence for the impact of concurrent partnerships on

HIV transmission, because of the possibility of ecological inference

fallacy. Now Reniers and Watkins demonstrate in an ecological study of

HIV prevalence in 34 sub-Saharan Africa countries that concurrency in

the traditional form of polygyny can even be negatively correlated with

HIV prevalence [12].

Published in final edited form as: AIDS. 2010 January 16; 24(2): 313–315.

doi: 10.1097/QAD.0b013e328333eb9d.

slide26
Concurrency is more complex than it seemsMirjam Kretzschmar,1,2 Richard G. White,3 and Michel Caraël4

It clearly shows the need to view concurrent partnerships in

their social and cultural context. It matters what the

motivation is for establishing concurrent partnerships, how

they are distributed among men and women, and in how far

they are anchored in the culture of a society.

Published in final edited form as: AIDS. 2010 January 16; 24(2): 313–315.

doi: 10.1097/QAD.0b013e328333eb9d.

slide27

It turns out that it is “mutual non-monogamy”

or “symmetric concurrency” that drives

STI/HIV spread….

Polygyny and symmetric concurrency: comparing long-duration sexually transmitted infection prevalence using simulated sexual networks

ShaliniSanthakumaran, Katie O\'Brien, Roel Bakker, Toby Ealden, Leigh Anne Shafer, Rhian M Daniel, Ruth Chapman, Richard J Hayes, Richard G White

Sex Transm Infect 2010;86:553-558 doi:10.1136/sti.2009.041780

Non-monogamy: risk factor for STI transmission and acquisition and determinant of STI spread in populations

Sevgi O. Aral, Jami S. Leichliter

Sex Transm Infect 2010;86:iii29-iii36 Published Online First: 5 October 2010 doi:10.1136/sti.2010.044149

the role of sti in hiv spread debate
….. “The role of STI in HIV spread” debate

Differences among

Mwanza

Rakai

Masaka ….

slide29

Perhaps we do not respect sexual structures adequately (or we do not integrate what we know about sexual structures into program design sufficiently)

slide30

Infections reflect where the epidemic is

Sexual structures and mixing patterns reflect where the epidemic is going

St. Petersburg;

Saratov;

?? Tallin

slide31

Take home message:

Sexual structures can be assessed through systematic rigorous

rapid assessments

slide32

migration and population movements of all kinds

where the infection is going

need to be considered in program planning and design

slide33

Movement networks and disease transmission

Networks of movements as explanation for spatio temporal spread of infections

Matt Keeling et al. PNAS, May 2010

a study of geographic profile of partnerships
A study of geographic profile of partnerships
  • Proportionately more long distance partnerships among gc infected compared to those with chlamydia
  • Proportionately more long distance partnerships among co-infected compared to those infected with gc or chlamydia
  • Proportionately more long distance partnerships among chlamydia repeaters compared to non-repeaters.
  • ? Implications for effectiveness of PN

Hippe and Jolly – In preparation

Jolly – personal conveersation

slide40

How well do we plan

and design prevention programs?

slide41

Do we determine prevention targets based on a good understanding of sexual structures?

slide42

Do we determine the intervention mix based on a good understanding of:

preventiontargets

affordability

sustainability

interactions with context

synergies and antagonisms among interventions

cost-effectiveness?

slide43

In program planning and design – do we consider the required coverage (for population impact)?

Do we plan adequately for scale-up?

Do our scale-up plans consider populations and health systems to be CAS’s?

slide44

Do we have the correct monitoring and evaluation plans in place?

      • Do we know what needs monitoring?
      • Do we know what can be effectively evaluated?
questions
Questions
    • Effect of an intervention?
  • or
    • Effect of the interaction between context and intervention?
questions con t
Questions (con’t)
  • Is it possible to tease out
  • the effects of a particular intervention on population incidence?
questions con t1
Questions (con’t)
  • Do Community Randomized Trials provide the best evidence for population impact of community interventions?
population health as complex adaptive system
Population health as complex adaptive system
  • Location
  • Life course perspective/ path dependence (chains of consequences)
  • Mutual determination

feedback loops (feedback – feed forward)

  • Dynamic aspects
  • Spatial aspects
  • Multilevel aspects
  • Interactions between levels
population health as complex adaptive system con t
Population health as complex adaptive system (con’t)
  • Interactions between determinants
  • There is heterogeneity and heterogeneity counts
  • Variance is important – it is the distribution (not central tendency) and tail of distribution that plays a real big role
  • Adaptation to feedback
  • Emergence; emergent properties

Need for agent-based modeling

slide52

“The reason to look at epidemiology from a complex systems approach is that it does not make sense to try any other approach”

Carl Simon

we do have tools
We do have tools
  • Systematic rigorous rapid assessments of context
  • Venue mapping – the “place” method
  • Mapping/monitoring of members of key populations
  • Geographic Information Systems (GIS)
  • Distribution analysis – Gini Coefficients and Lorenz Curves
  • Resource allocation decision making tools
  • Cost, cost-benefit, cost effectiveness analyses
  • Mathematical modeling – for targeting and coverage issues

(• Agent based modeling for emergent properties)

  • CAS based approaches to scale-up
  • New approaches to M&E being developed
what we need is
What we needis

not a paradigm shift

but a major paradigm enhancement

An expanded approach to bring “population health”

and “complexity science” approaches into STI/HIV

prevention.

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