HIV Risk Factors and Injection Drug Use among Men who Have Sex with Men in Unguja Island, Zanzibar,

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HIV Risk Factors and Injection Drug Use among Men
who Have Sex with Men in Unguja Island, Zanzibar,
Tanzania
A. Holman1, M. Dahoma2, L. Johnston3, K. Sabin4,
A. Othman2, R. Martin5, A. Kim4, M. Mussa2, C.
Kendall6, T. Kibuka5, L. Nganga5
1Association of Schools of Public Health/Centers
for Disease Control Tanzania
2 Zanzibar AIDS Control Program, Ministry of
Health and Social Welfare 3 Tulane University Sch
ool of Public Health and Tropical Medicine
4 HHS-Centers for Disease Control and Prevention,
Global AIDS Program, Atlanta, United States
5HHS-Centers for Disease Control and Prevention,
Global AIDS Program, Tanzania
2
Zanzibar

• 2 islands forming semi-autonomous territory of
  the United Republic of Tanzania Unguja and
  Pemba.
  
• Estimated population 1.1 million (2002 Census)
• Agriculture-based economy Popular tourist
  destination
  
• 99 Muslim

Source www.lib.utexas.edu/maps/tanzania.html
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Background

• Zanzibar has a concentrated HIV epidemic.
• HIV prevalence is (Tanzania HIV/AIDS and Malaria Indicator Survey,
  2007-08)
  
• Several hidden populations with documented or
  presumed increased risk for HIV
  
• Injection-drug users
• Illegal and increasingly common practice
• HIV prevalence 26 (2005)
• Men who have sex with men (MSM)
• Illegal practice according to Zanzibar law
• No information on sex or drug-use practices
• Seroprevalence and behavioural survey conducted
  in 2007 among MSM in Unguja island provides
  opportunity to study prevalence of drug-use, sex
  practices, and HIV in this population

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Objective

• To describe drug-use and sexual practices and
  prevalence of HIV and other selected infections
  among injection drug-using MSM in Unguja Island,
  Zanzibar.

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Methods Respondent-driven sampling (RDS)

• Chain-referral sampling method adapted to
  attain probability-based sample of hidden
  populations based on social network theory
  (Heckathorn 2007).
• Appropriate method for sampling highly socially
  networked populations, e.g. MSM in Zanzibar
  
• Recruitment
• Initial recruits (seeds) identified through
  formative research and peer-educator contacts.
  
• Successive waves of recruitment until sample size
  is reached.
  

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RDS Recruitment
Seed
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RDS Recruitment
Wave 1
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RDS Recruitment
Wave 1
Wave 2
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Wave 1
Wave 2
Wave 3
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Wave 1
Wave 2
Wave 3
Wave 4
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Wave 1
Wave 2
Wave 3
Wave 4
Wave 5
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Study design (1)

• 10 seeds selected through formative research to
  initiate recruitment.
  
• April to June 2007, 509 MSM enrolled in survey.
• Eligibility Men aged 15 years, living in Unguja
  and reporting engaging in anal sex with another
  man within 3 months before the survey.
  
• Dual incentives
• US5 for participation in study
• US1.75/peer successfully recruited into the
  study
  

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Study design (2)

• Data collected
• Interview (119 items)
• Socio-demographic and network questions
• Sexual practices
• Injection and non-injection drug use practices
• HIV knowledge, risk perception, and previous HIV
  testing history
  
• Venipuncture blood sample
• HIV rapid-test-based serial algorithm SD
  Bioline HIV-1/2 3.0, Determine HIV ½ test,
  Unigold
  
• Hepatitis C ACON virus test strip
• Hepatitis B ACON virus test strip
• Syphilis ACON Syphilis Ultra Rapid Test strip

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Data Analysis

• Adjusted proportion estimates (weighting based on
  participants probability of recruitment) and 95
  confidence intervals calculated with RDS Analysis
  Tool 5.6 (RDSAT)
• 2. Unadjusted and adjusted odds ratios calculated
  in STATA 9.0 using weights generated in RDSAT.
  

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Socio-demographic characteristics of study
population (N509)
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Proportion of MSM reporting injection drug use,
Unguja, Zanzibar
IDU MSM (N66)

• Groups similar in marital status and education
• IDU-MSM more likely to be 25 years or older (UOR
  3.4, CI. 1.6 - 8.5).
  

Non-IDU MSM (N442)
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Injection drug use practices among MSM, Unguja,
Zanzibar (N66)
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Reported previous month sex practices among IDU
MSM (N66) vs. non-IDU MSM (M442) in Unguja,
Zanzibar
95 CI
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Reported sexual practices, risk perception and
HIV testing among non-IDU MSM (N442) and IDU MSM
(N66) in Unguja, Zanzibar
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Prevalence of HIV and STIs among non-IDU MSM
(N442) and IDU MSM (N66) in Unguja, Zanzibar
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Conclusions

• RDS a successful approach for recruitment of
  hidden populations potential for use to
  deliver prevention interventions and services.
  
• Injection drug use is associated with higher risk
  sexual practices, unsafe injection practices and
  HIV infection among MSM.
  
• High rates of unprotected sex with female and
  male partners potential to serve as a bridge for
  HIV transmission between non-IDU MSM,
  heterosexual IDU, female partners and the general
  population.
• Poor access to HIV testing and related services.

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Recommendations

• Need for targeted interventions for MSM IDU
  accounting for the overlap of high-risk sexual
  and drug using networks STI testing and
  treatment, HIV counseling, testing, care and
  treatment, and linkages to IDU services.
• Since dissemination meeting among stakeholders in
  November 2007, community-based peer educator
  initiatives for HIV prevention within the MSM
  community have been significantly scaled up.
  These initiatives should be provided ongoing
  support and links to existing services should be
  facilitated.

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Acknowledgements

• Study participants and peer educators
• Zanzibar study staff
• Zanzibar AIDS Control Programme, Ministry of
  Health and Social Welfare
  
• Tulane University School of Public Health and
  Tropical Medicine
  
• Centers for Disease Control and Prevention
  Tanzania Atlanta
  

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For more information

• Dr. Mohammed Dahoma
• Zanzibar AIDS Control Programme
• zacp_at_zanlink.com
• Abigail Holman
• Centers for Disease Control and Prevention -
  Tanzania
  
• holmana_at_tz.cdc.gov