Incentivising safe sex: a randomised trial of conditional cash transfers for HIV and sexually transmitted infection prevention in rural Tanzania

Abstract

ObjectiveThe authors evaluated the use of conditional cash transfers as an HIV and sexually transmitted infection prevention strategy to incentivise safe sex.DesignAn unblinded, individually randomised and controlled trial.Setting10 villages within the Kilombero/Ulanga districts of the Ifakara Health and Demographic Surveillance System in rural south-west Tanzania.ParticipantsThe authors enrolled 2399 participants, aged 18–30 years, including adult spouses.InterventionsParticipants were randomly assigned to either a control arm (n=1124) or one of two intervention arms: low-value conditional cash transfer (eligible for $10 per testing round, n=660) and high-value conditional cash transfer (eligible for $20 per testing round, n=615). The authors tested participants every 4 months over a 12-month period for the presence of common sexually transmitted infections. In the intervention arms, conditional cash transfer payments were tied to negative sexually transmitted infection test results. Anyone testing positive for a sexually transmitted infection was offered free treatment, and all received counselling.Main outcome measuresThe primary study end point was combined prevalence of the four sexually transmitted infections, which were tested and reported to subjects every 4 months: Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Mycoplasma genitalium. The authors also tested for HIV, herpes simplex virus 2 and syphilis at baseline and month 12.ResultsAt the end of the 12-month period, for the combined prevalence of any of the four sexually transmitted infections, which were tested and reported every 4 months (C trachomatis, N gonorrhoeae, T vaginalis and M genitalium), unadjusted RR for the high-value conditional cash transfer arm compared to controls was 0.80 (95% CI 0.54 to 1.06) and the adjusted RR was 0.73 (95% CI 0.47 to 0.99). Unadjusted RR for the high-value conditional cash transfer arm compared to the low-value conditional cash transfer arm was 0.76 (95% CI 0.49 to 1.03) and the adjusted RR was 0.69 (95% CI 0.45 to 0.92). No harm was reported.ConclusionsConditional cash transfers used to incentivise safer sexual practices are a potentially promising new tool in HIV and sexually transmitted infections prevention. Additional larger study would be useful to clarify the effect size, to calibrate the size of the incentive and to determine whether the intervention can be delivered cost effectively.Trial registration numberNCT00922038 ClinicalTrials.gov.

A global comprehensive review of economic interventions to prevent intimate partner violence and HIV risk behaviours

“…Two studies were conducted in sub-Saharan Africa (SSA) [40,41] and one in the USA [42]. In general study design was rigorous, using RCTs in two studies [40,41] and a quasi-experimental design in the other [42]. In Tanzania remaining STI-free was incentivised with cash and assessed through testing every 4 months over a 12-month period [40].…”

“…In general study design was rigorous, using RCTs in two studies [40,41] and a quasi-experimental design in the other [42]. In Tanzania remaining STI-free was incentivised with cash and assessed through testing every 4 months over a 12-month period [40]. In Malawi a study focused on incentivising maintaining HIV status over 12 months for women and men (if HIV-negative at start, maintaining this; if HIV-positive, they automatically received the cash transfer at the end) [41].…”

“…In Tanzania, adjusted analysis showed significant impacts of high-value incentives on remaining STI-free [40]. In Malawi, however, there was no impact on maintaining HIV-status [41].…”

Which strings attached: ethical considerations for selecting appropriate conditionalities in conditional cash transfer programmes

“…Many programmes, however, target behaviours with corresponding health benefits that require ongoing maintenance. For example, the RESPECT programme in Tanzania incentivised safe sex practice, as measured by negative sexually transmitted infection (STI) tests, showing a positive effect during the period of payment 26. Yet the qualitative study and post-intervention follow-up for this trial suggested a need for ongoing cash payment to sustain protection among female participants.…”

“…Conditioning on outcomes that are significantly influenced by genetic predisposition and physiology can discriminate against many deserving beneficiaries. The RESPECT trial in Tanzania presents an example where biological and social factors contributed to women's being disproportionately disadvantaged in attaining the conditionality 26. The programme conditioned payments on negative STI tests as a proxy for safe sex.…”