CAPRISA is the UNAIDS Collaborating Centre for HIV Research and Policy Impact of conditional cash incentives on HSV-2 and HIV in rural high school students

CAPRISA is the UNAIDS Collaborating Centre forHIV Research and Policy

Impact of conditional cash incentives on HSV-2 and HIV in rural high school students in South Africa

Quarraisha Abdool Karimon behalf of the CAPRISA 007 team

Associate Scientific Director: CAPRISAProfessor in Clinical Epidemiology, Columbia University

Adjunct Professor in Public Health, University of KwaZulu-Natal

CAPRISA 007 matched-pair cluster randomized controlled trial

Background• Conditional cash incentives have been effective for a

range of behaviours such as smoking cessation, vaccination uptake and drug rehabilitation

• Promising data that incentives may reduce risky sexual behaviours and impact HIV transmission:

– Baird et al: incentivized school attendance reduced HIV and HSV-2 prevalence in Malawi

– Duflo et al: incentivized later sexual debut reduced pregnancy rates & increased age at sexual debut in Kenya

– Björkman-Nyqvist et al – community lotteries reduced HIV incidence in Lesotho

• Ongoing high HSV-2 and HIV rates in adolescent girls in Africa, with few prevention options…

Age Group (years)

Prevalence of HIV infection% (95% Confidence Interval)

Male (n=1252) Female (n= 1423)

15 1.0

16-17 1.118-19 1.5

≥ 20* 1.8

HIV & HSV-2 prevalence in students by age

Prevalence of HSV-2 (Herpes simplex virus type-2)

15 0.7

16-17 2.018-19 6.6

≥ 20* 3.5

2.6

6.1

13.6

24.7

3.5

9.3

30.2

43.3*Small sample size in the > 20 year sub-group

Purpose

To assess the impact of

conditional cash incentives on the

incidence of HSV-2 and HIV infection

in rural high school students

in South Africa

Study design and Data analysis• 14 schools matched as 7 pairs: by school enrolment

size, geographical proximity & school pass rates

• Grade 9 & 10 students (n = 3,217 students)

• Parental consent with student assent

• HIV and HSV-2 testing (serology): Baseline; 12 months (91% retained) & 24 months (85% retained)

Baseline HSV-2 prevalence: Intervention: 9.0% Control: 7.3%

Baseline HIV prevalence: Intervention: 4.7% Control: 3.7%

• Analysis performed at the cluster level using paired t-tests (Inter-cluster correlation = 0.01)

Students enrolled, followed & analysed for HSV-2 incidence analysis

Intervention

• All 14 rural schools participated in a local Lifeskills (incl. HIV education) Program - My Life! My Future!

• One school in each of 7 pairs randomly assigned to receive, in addition, cash incentives for any combination of 4 conditions being met:

– 80% quarterly participation in My Life! My Future! (4/year)

– Attaining passing score in 6-monthly academic tests (2/yr)

– an annual HIV test (1/yr)

– Submit report on their community project at end (once off).

• Maximum incentive possible is R1,750 ($1=R10), equivalent to half the local child care grant

Most cash incentives were for HIV testing & the Lifeskills Program attendance – no impact on school performance & few completed report

Incentivized Conditions

InterventionGroup

ControlGroup

HIV Counselling and Testing (Annual)Early in study 51.8 (689) 40.4 (560)Mid-study 59.2 (787) 36.6 (507)Close to end of the study 45.2 (601) 8.9 (124)

“My Life! My Future!” Lifeskills & HIV educational Program (Quarterly)1st quarter in study 37.6 (500) 30.6 (424)Mid-study quarter 41.4 (551) 26.8 (372)Final quarter in study 45.1 (600) 27.0 (374)

Academic School Performance (6 monthly)First semester in study 18.6 (248) 22.7 (314)Last semester in study 37.2 (495) 45.4 (629)

Community project report 12.0 (159) 3.3 (46)

Effectiveness of conditional cash incentives in preventing HSV-2 and HIV

HSV-2 Incidence rate ratio*: 0.70 (CI: 0.57 to 0.86); p = 0.007

Intervention Group Control Group

# HSV-2 infections 136 183

Person-years (# students) 2091 (1329) 2132 (1384)

HSV-2 incidence/100 py 6.2 8.7

* Note: Analysis based on matched-pairs of schools & not individual students







HIV incidence / 100 py 1.8 1.5


Too few HIV infections (n=75) to assess impact on HIV



30% lower HSV-2 incidence with cash incentives





HIV incidence / 100 py 1.8 1.5


Too few HIV infections (n=75) to assess impact on HIV

Kaplan-Meier survival probability for HSV-2 and HIV infection

* Note: Analysis based on individual students

*

HSV-2 risk: Control students

HSV-2 risk: Interventionstudents

HIV risk: Intervention students

HIV risk: Control students

p = 0.007

p = 0.419

HSV-2 incidence by incentive levels

* Note: Analysis based on individual students

*

*

• CCI boys had 40% lower HSV-2 incidence (p = 0.042)

• CCI girls had 24% lower HSV-2 incidence (p = 0.035)

• Too few HIV endpoints for HIV sub-group analyses. HIV

incidence lower than expected - need a sample size 3-5 times

larger for adequate power to assess 30% impact on HIV prevention

Students who got > $95 had71% lower HSV-2 Incidence

(p = 0.034)

Conclusions• Cash incentives: 30% reduction in HSV-2 incidence

• Context for cash incentives important:– This study is in poor rural high school students in S. Africa– Few (< 1/3) conditions met, hence median cash incentive = $60– Cash incentives for school performance made little impact– Impact: ↑ uptake of HIV tests and lifeskills program attendance– Incentive dose-response should be interpreted with caution

• Could not establish impact of cash incentives on HIV – lack of statistical power due to lower than expected HIV

incidence (?background trend, ?community interventions ?

study-related interventions)

• Structural interventions in the real world - Challenging!

Acknowledgements KwaZulu-Natal Department of Education Provincial and District and

Circuit Offices Pietermaritzburg and Vulindlela

School Governing Boards, students and staff at the schools

MiET Africa

CAPRISA 007 study team: Quarraisha Abdool Karim, Kerry Leask, Ayesha Kharsany, Hilton Humphries, Fanele Ntombela, Natasha Samsunder, Cheryl Baxter, Janet Frohlich, Lynn van der Elst & Salim S. Abdool Karim

This material is based upon work supported by the Embassy of the Kingdom of Netherlands (EKN) under activity number 20336 through a subcontract with MiET Africa.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and therefore the EKN does not accept any liability in regard thereto.

Documents

CAPRISA is the UNAIDS Collaborating Centre for HIV Research and Policy Impact of conditional cash incentives on HSV-2 and HIV in rural high school students