Presentation on theme: "ASSESSING RISK COMPENSATION POST-VOLUNTARY MEDICAL MALE CIRCUMCISION IN ZAMBIA Paul C. Hewett a, Petra Todd b, Nicolas Grau c, Erica Soler- Hampejsek c,"— Presentation transcript:
ASSESSING RISK COMPENSATION POST-VOLUNTARY MEDICAL MALE CIRCUMCISION IN ZAMBIA Paul C. Hewett a, Petra Todd b, Nicolas Grau c, Erica Soler- Hampejsek c, Kumbutso Dzekedzeke d, Barbara S. Mensch c a Population Council, Zambia, b University of Pennsylvania, c Universidad de Chile, d Population Council, New York, e Dzekedzeke, Inc.
Background Government of the Republic of Zambia has set ambitious targets for scaling up voluntary medical male circumcision (VMMC) services. Target: MC 2.0 million HIV negative men aged 15−49, approximately 80% of the eligible population by 2015. Objectives of this analysis: Assess risk compensatory behaviors post MC Focus on men in a population based cohort Across 2 years of observation Assessing 6 indictors of risk behavior Estimation methods account of selectivity of uptake of circumcision
Kisumu, Kenya : Mattson et al., 2008 (sub-study) Propensity score of 18 risk behaviors Incident infections of gonorrhea, chlamydia, trich No stat sign. differences: MC, not MC; all declined HIV testing and counseling: 1m, 3m, 6m, 12m Rakia, Uganda: Gray et al., 2012 Post-trial FU for 2-years (control, MC) - 22% no MC No observable self-selection MC, ~MC Sex active 12m, # partners, condom use, alcohol No stat. sign. differences MC & non-MC HIV testing & health education : Enroll, 6m, 12m, 24m Risk compensation: Evidence
Question What about risk compensation in a program with national scale and less intensive counseling and follow-up? Example: Zambia Over 725,000 circumcisions conducted since 2008.
Methods Since 2010, PC has been annually following a representative cohort of men & women in Zambia. Primary objective: To assess the prevalence of risk compensation post-VMMC. Information collected: Demographics VMMC Knowledge, beliefs and attitudes VMMC status and timing Sexual behavior and experiences of STIs Perceptions of HIV risk
Methods (cont.) To-date, the study has collected three rounds of data within a 24 month timeframe Round 1 Nov 2010 to Apr 2011 Round 2 Sep 2011 to Dec 2011 Round 3 Sep 2012 to Jan 2013 Round 4 Oct 2013 to Feb 2014 Round 1Round 2Round 3 N233419681920 R1-R2R1-R3 Response rate818482 Attrition rate--1618
Methods (cont.) Indicators assessing risk compensation Sex with 2+ partner in last year Unprotected sex Sex after alcohol use Experience of STI symptom in last year Paid for sex in last year Statistical Analysis Instrumental variables GMM regression Logit regression with fixed effects Difference-in-difference matching Estimation approaches addresses endogeneity of circumcision uptake
Results – MC Uptake Since 2008 through early 2013… 21% of sample men were recently circumcised 16% between R1 (2010) & R3 (2013). 5% 12% 21%
Results – Risk Compensation IV GMM Logit FE Diff-Diff ATT Sex w/2+ partners Circumcised-1.2 (.67) †.05 (.03) †.05 (.05) Unprotected sex Circumcised-.85 (.57)-.07 (.03)*-.03 (.06) Sex & alcohol use Circumcised1.61 (1.06).02 (.03)-.07 (.07) STI symptom Circumcised-.08 (.27).01 (.02)-.06 (.03)* Paid for Sex Circumcised-1.39 (.65)*.03 (.02).09 (.04)* † p <.10; * P <.05 Note: models includes covariate controls
Conclusions 10 Source: Hallet et al., 2008 – Southern Africa MC men may be less risky than uncircumcised No evidence of risk compensation in 2-years Controlling for endogeneity of circumcision uptake…
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