Transcript friedman-networks and interventions2

Networks and interventions
Acknowledgements
USA National Institute on Drug Abuse
• Social Factors and HIV Risk (R01 DA06723)
• Drug use and HIV risk among youth (R01 DA10411 )
• Networks, norms and HIV risk among youth (R01
DA13128)
USA National Institute on Mental Health
• Local context, social-control action, and HIV risk (R01
MH62280)
• Hundreds of Bushwick residents and others who
participated in these studies
• Many collaborators and co-authors
Social Networks and HIV: Introduction
of some concepts
1. Risk networks, social networks, and the
spread of HIV and of social influence
2. Network-based interpretations of
intervention models
Most HIV epidemiology, prevention, and policy
has focused on individual knowledge, attitudes,
personality and behaviors:
²
•
•
¾
¾
€
€
•
€
•
¾
•
¾
²
•
•
€
¾
²
•
¾
€
¾
²
People also have social and behavioral ties
of various types and strengths
²
•
•
¾
¾
€
€
•
€
•
¾
•
¾
²
•
•
€
¾
²
•
¾
€
¾
²
Risk network ties can carry infections:
Within relationships
To or from an individual
Throughout a community or small group
The concepts of network components and
cores
• Two components; Seidman K-2 core is in
red
Research has shown that network location
affects probabilities of infection
• Thus, the probability that an infected
person who engages in risky behavior will
do so with an uninfected partner depends
on their network locations.
• As does the probability that an uninfected
person who engages in risky behavior will
do so with an infectious person
• Cores and other microstructures of dense
risk interaction are associated with higher
seroprevalence
These thoughts lead to the following insight:
HIV incidence is a socially-conditioned probability
It depends on:
• Risk behavior
• Between at least two people, one of whom is
uninfected and another of whom is infectious
• The susceptibility of the uninfected person (and thus,
e.g., on STDs, which are unevenly distributed in
networks and society)
• The infectiousness of the infected (and thus, on time
since infection, on HAART use, and on STDs, which
are all unevenly distributed in networks and society)
• For a given uninfected person, the probability that a
partner is infected depends on the partners’ place in
community networks
–
–
Friedman SR, Jose B, Neaigus A, Goldstein M, Mota P, Curtis R, Ildefonso G, Des Jarlais DC. Multiple
Racial/Ethnic Subordination and HIV among Drug Injectors. In: M Singer (Ed.), The Political Economy
of AIDS. Amityville, New York: Baywood Press, 1998. pp. 105-127.
Friedman SR, Jose B, Neaigus A, Curtis R, Vermund SH, Des Jarlais DC. (2000). Network-related
mechanisms may help explain long-term HIV-1-seroprevalence levels that remain high but do not
approach population-group saturation. American Journal of Epidemiology, 152 (10), 913-922.
Risk is a conditional probability
+, on HAART
-
Negative
Unknown, but GC+ and HSV-2+
The probability is socially structured
IDUs may be in sexual networks that contain
non-injecting drug users and thus sexual
transmission may extend to the community
HIV-positive by Gender/Sexuality (MSM=up triangle, WSW=down triangle, other
female=circle, other male=square) by Hardest Drug Use Ever (from dark red to light
pink: IDU, Crack, NI Heroin or Cocaine; blue=other)
SOCIAL network ties can carry influence:
Within relationships
To or from an individual
Throughout a community or small group
Analyses of behaviors within relationships find:
Risk and transmission behaviors are independently and
significantly more likely in close relationships
Behavior
Relationship
characteristic
Citation
Failure to use condoms
consistently
very close;
spouse/lover
Friedman
et al 1994,
2001, in
press
Receptive syringe sharing
very close;
long duration;
steal together
Neaigus
et al 1995
Distributive
syringe sharing
by HIV+ IDUs
very close;
spouse/lover
Friedman
et al 1996
Both drug users and their neighbors may be (or become)
active in communicating health messages: survey
findings about other-protective action in the prior 3
months by “hardest” drug used in last 3 months
In the last 3 months,
have you urged …
160 61
IDUs crack
smok
ers
80 users of
noninjected
heroin or
cocaine
90
marijuan
a users
75 nonusers of
these
drugs
46% 56%
56%
64%
55%
51% 64%
54%
48%
41%
to get into drug
treatment?
54% 64%
40%
28%
25%
to use needle
exchanges?
38% 13%
15%
2%
4%
anyone
to use condoms if
they start a new
relationship?
not to use drugs?
any drug injectors:
Research in many countries shows that
safer norms are associated with safer
behaviors such as consistent condom use
and avoiding syringe sharing
• Urging others to behave more safely creates
“external” social norms that flow through social
networks
Prevention issues
Network concepts let us develop ideas that focus
on:
1. The individual client
2. The relationship
2. The client’s friends and partners
3. The risk community as a whole
4. The peer structure of communities that are trying
to organize prevention and care
This helps us get “outside of the box” of thinking
only about the individual, but also keeps us from
forgetting about her or him
Network Interventions
• Sessions in which IDUs bring in their peers can
help reduce the index IDU’s risk behaviors
(Latkin)
• Diffusion and indigenous leadership models of
behavior and normative change have been shown
to work by outreach projects and by Jeff Kelly
and Wayne Wiebel
• Risk contact tracing
• Social contact tracing
Diffusion
Influence, supplies,
OW
information
OW
Issues:
Cultural acceptability
Tipping points in egocentric networks
Number of outreach workers (OWs)
Secondary distribution of supplies (for
syringe exchanges, this has been both
promoted and questioned)
Secondary syringe exchange
• Staff (often users or members of users’ friendship networks)
give clients needles and other supplies to take to others and to
retrieve if feasible
• Staff train clients in best ways to do this, including perhaps
in referrals and recruitment; and learn from the secondary
exchanger clients
• Secondary exchangers may train members of their
distribution networks to be secondary exchangers too
• It can incorporate thousands of new IDUs into harm
reduction activity. “Bundles” of supplies may be quite large.
• Evaluation by sequential cross-sectional design, with
behavioral, normative and infection outcomes.
• Sampling perhaps by targeted sampling or respondent driven
sampling
• Tom Valente has studied secondary exchange
Indigenous-Leadership-Focused Models
L ocal
L ead er
L ocal
L ead er
OW
In flu en ce, i nformatio n
su p pli es
L ocal
L ead er
OW
L ocal
L ead er
F riend sh ip , r esp ect, in flu en ce
in fo rmation , sup p lies
Local leaders have their own interests at stake, and their
own conceptions of risk and benefit. This may partially
explain difficulties in replications of Kelly’s intervention
in Glasgow and London gay venues.
Organizing communities for intervention and
support
• Users’ groups exist and are engaged in
fighting HIV and in providing advice to policy
makers and programs in many countries
• So also do projects in which other community
members and users work together
• In general, community organizing is built
around members or participants recruiting
their social networks to take part
• This has been shown both by empirical
studies of social movements and by historical
analyses of successful organizing efforts in a
wide range of activities
Concluding thoughts (1)
• Networks can be used to recruit, to convey messages,
to distribute supplies
• Their existence creates “contamination” problems for
some individual-focused research designs
• A good program reduces HIV incidence and other
harms. These harms are created by behaviors within
networks, not just by disembodied behaviors.
• Reducing risk behavior (by the uninfected) and
transmission behavior (by the infected) can have
different implications depending where they are in
community social networks and on the characteristics
of their partners
• This implies that evaluating programs simply in terms
of reducing risk behavior may be misleading.
Concluding thoughts (2): Program approach
• Street-based SEPs staffed in part by current IDUs and
other network members
• Secondary syringe exchange and condom distribution
• Diffusion of information and persuasive arguments
through networks
• Help users to organize to give advice and to take part
in policy discussions
• Can greatly increase numbers, social network
distribution, and geographic distribution of the
intervention
• IF and ONLY IF the users’ culture and the general
social and political environment allow it.