A complex community-based intervention implemented in Zimbabwe has failed to reduce the incidence of new HIV infections in the population. Researchers from the United Kingdom, Zimbabwe and South Africa studied the impact of an integrated community and clinic-based intervention programme, one strategy thought to have potential to promote behaviour change. However, despite “greater programme activity and knowledge in the intervention communities”, no significant difference in HIV incidence was found between the control and intervention communities, an effect in part blamed on the dire economic situation in the country.
Sub-Saharan Africa has been heavily affected by the HIV epidemic, with one-fifth of the population infected in Zimbabwe. Although this proportion has been declining slowly, there remains little direct evidence that interventions that seek to prevent HIV infections have a beneficial impact.
Both syndromic management of sexually transmitted infections (STIs) and peer education have been found beneficial in some community-based trials, but not in others. Integrated interventions that combine community based prevention efforts with clinic-based STI treatment have thus been proposed as potentially feasible and effective strategies to reduce population HIV incidence.
Simon Gregson from Imperial College London, UK, and colleagues tested this hypothesis in a cluster randomised controlled trial in eastern Zimbabwe (PLoS Med 4(3): e102. doi:10.1371/journal.pmed.0040102).
Six pairs of communities were randomly allocated to receive the intervention or to act as controls, which received the standard governmental interventions of basic STI management, condom distribution and education measures.
All individuals in the age groups expected to have the highest HIV incidence (males aged 17-54 years and females aged 15-44 years) were eligible for enrolment, although given that spouses of infected individuals have an increased risk of infection, only one individual from each marital couple were included to enhance statistical power.
Over a three-year period, the intervention strategies were implemented by two non-governmental organisations – the Family AIDS Caring Trust and the Biomedical Research and Training Institute – and the Zimbabwe Ministry of Child Health and Welfare.
The programme had three main components: peer education and condom distribution among commercial sex workers and male clients, supported by income-generating projects for unmarried women to reduce reliance on sex work; strengthened syndromic STI management at local health centres; and educational open days at health centres to promote safer sexual behaviour and increase uptake of STI treatment. Baseline HIV prevalence was 24% in intervention communities and 21% in control communities.
The team reports that men who attended programme meetings had lower HIV incidence (incidence rate ratio 0.48, 95% CI 0.24–0.98), and less unprotected sex with casual partners (odds ratio 0.45, 95% CI 0.28–0.75). Also, more men in the intervention communities reported cessation of STI symptoms (odds ratio 2.49, 95% CI 1.21–5.12).
However, despite these changes, no difference was detected in the primary outcome of HIV incidence rate ratio, which was 1.27 (95% CI 0.92–1.75) compared to the control communities. No evidence was found for reduced incidence of self-reported STI symptoms or high-risk sexual behaviour in the intervention communities.
Importantly, more young women in the intervention communities had started sex or had unprotected sex with a casual partner, while the income-generating projects “proved impossible to implement in the prevailing economic climate”.
The Zimbabwean economic situation has been dire for some time, with high inflation, mass unemployment, and a cost of living far out of proportion to income. A recent national strike was called by unions to protest against the government's economic mismanagement, corruption and oppression, although many workers did not heed the call, thought to be due to fears of the economic impact of the stay away.
Latest figures from the UN Food and Agriculture Organization suggest almost half the Zimbabwean population is undernourished, while the situation has worsened since then.
In an editor's summary accompanying the report, the editor of PloS Medicine concludes that “trials such as this are very difficult to design, carry out, and interpret. In particular, if a complex intervention such as this fails, it is often hard to tell whether it did so because the intervention was not delivered successfully, or because it did not work”.
The authors note that the trial was underpowered to detect a small difference in HIV incidence, although no trends towards such an effect were seen on a population level. Moreover, they note that the effect of education programmes in the control communities could have limited the ability to detect an effect of the intervention programme.
The apparent detrimental effects of the intervention on young women's sexual behaviour could be explained by an increased willingness to report such behaviour rather than an actual increase in such behaviours.
However, the authors also highlight the importance of economic decline in reducing the effectiveness of the intervention programme.
“Preliminary findings from subsequent qualitative investigations indicate that, in the predominantly rural communities in which the study was conducted, poverty and the associated failure of income-generating projects meant that some peer educators were unable to maintain safer behaviours.
“Given their increased visibility within the community—intended to enhance their status and self-esteem and, thus, to reinforce their commitment to and role as models for behaviour change—they may, inadvertently, have served as negative role models and, thereby, may have contributed to the greater female early-age sexual activity.”
The authors conclude that, given the economic conditions, unmarried women could still play a useful role in interventions targeted at beer halls.