Structural approaches to HIV prevention

Behavioral mechanisms in HIV epidemiology and prevention: past, present, and future roles

In the 1980s, behavioral variations across geographically and socially defined populations were the central focus of AIDS research, and behavior change was seen as the primary means of controlling HIV epidemics. Today, biological mechanisms--especially other sexually transmitted infections, antiretroviral therapy, and male circumcision--predominate in HIV epidemiology and prevention. We describe several reasons for this shift in emphasis. Although the shift is understandable, we argue for a sustained focus on behavioral mechanisms in HIV research in order to realize the theoretical promise of interventions targeting the biological aspects of HIV risk. We also provide evidence to suggest that large reductions in HIV prevalence may be accomplished by small changes in behavior. Moreover, we contend that behavioral mechanisms will find their proper place in HIV epidemiology and prevention only when investigators adopt a conceptual model that treats prevalence as a determinant as well as an outcome of behavior and that explicitly recognizes the dynamic interdependence between behavior and other epidemiological and demographic parameters.

Effects of neighbourhood-level educational attainment on HIV prevalence among young women in Zambia

BACKGROUND

Investigations of the association between socio-economic position indicators and HIV in East, Central and Southern Africa have chiefly focused on factors that pertain to individual-level characteristics. This study investigated the effect of neighbourhood educational attainment on HIV prevalence among young women in selected urban and rural areas in Zambia.

METHODS

This study re-analysed data from a cross-sectional population survey conducted in Zambia in 2003. The analyses were restricted to women aged 15-24 years (n = 1295). Stratified random cluster sampling was used to select 10 urban and 10 rural clusters. A measure for neighbourhood-level educational attainment was constructed by aggregating individual-level years-in-school. Multi-level mixed effects regression models were run to examine the neighbourhood-level educational effect on HIV prevalence after adjusting for individual-level underlying variables (education, currently a student, marital status) and selected proximate determinants (ever given birth, sexual activity, lifetime sexual partners).

RESULTS

HIV prevalence among young women aged 15-24 years was 12.5% in the urban and 6.8% in the rural clusters. Neighbourhood educational attainment was found to be a strong determinant of HIV infection in both urban and rural population, i.e. HIV prevalence decreased substantially by increasing level of neighbourhood education. The likelihood of infection in low vs. high educational attainment of neighbourhoods was 3.4 times among rural women and 1.8 times higher among the urban women after adjusting for age and other individual-level underlying variables, including education. However, the association was not significant for urban young women after this adjustment. After adjusting for level of education in the neighbourhood, the effect of the individual-level education differed by residence, i.e. a strong protective effect among urban women whereas tending to be a risk factor among rural women.

CONCLUSION

The findings suggested structural effects on HIV prevalence. Future research should include more detailed mapping of neighbourhood factors of relevance to HIV transmission as part of the effort to better understand the causal mechanisms involved.

Men who have sex with men and HIV/AIDS in sub-Saharan Africa

Globally, men who have sex with men (MSM) continue to bear a high burden of HIV infection. In sub-Saharan Africa, same-sex behaviours have been largely neglected by HIV research up to now. The results from recent studies, however, indicate the widespread existence of MSM groups across Africa, and high rates of HIV infection, HIV risk behaviour, and evidence of behavioural links between MSM and heterosexual networks have been reported. Yet most African MSM have no safe access to relevant HIV/AIDS information and services, and many African states have not begun to recognise or address the needs of these men in the context of national HIV/AIDS prevention and control programmes. The HIV/AIDS community now has considerable challenges in clarifying and addressing the needs of MSM in sub-Saharan Africa; homosexuality is illegal in most countries, and political and social hostility are endemic. An effective response to HIV/AIDS requires improved strategic information about all risk groups, including MSM. The belated response to MSM with HIV infection needs rapid and sustained national and international commitment to the development of appropriate interventions and action to reduce structural and social barriers to make these accessible.

HIV in adolescents in sub-Saharan Africa

PURPOSE OF REVIEW

In this review, we summarize existing evidence on the effectiveness of different intervention approaches to HIV prevention in adolescents - focusing on studies that are either from or are relevant to sub-Saharan Africa. In addition, we include a brief review of other salient issues relevant to HIV prevention research in adolescents.

RECENT FINDINGS

Although numerous adolescent behavioural HIV prevention interventions have been evaluated, few have assessed their impact on HIV endpoints or been undertaken in Africa. In the three trials from Africa, which had HIV endpoints, none of the interventions had an impact on HIV, although all affected some knowledge and attitudes and reported behaviours. In one of these trials, there was a borderline effect on herpes simplex virus-2 incidence. Adolescents have typically been excluded from trials of biological interventions, although they are likely to benefit from these interventions if found to be effective. Despite the regulatory difficulties, they must be considered for inclusion in these trials as an important target population. Although structural determinants of infection appear to be key drivers of the epidemic in young people in sub-Saharan Africa, few have been rigorously evaluated; those that have have been shown to be promising evidence for their future role in prevention.

SUMMARY

Young people in sub-Saharan Africa, particularly young women, continue to bear the brunt of the HIV epidemic. Adolescents must be an important focus for HIV prevention programming and research. It is increasingly clear that multilevel approaches to prevention will be required to reduce rates of HIV in this age group.

HIV-prevention science at a crossroads: advances in reducing sexual risk

PURPOSE OF REVIEW

We review the current state of evidence-based prevention strategies for reducing sexual transmission of HIV. The combined programmatic and scientific efforts through 2008 to reduce sexual transmission of HIV have failed to reduce substantially the global pandemic.

RECENT FINDINGS

Prevention interventions to reduce HIV infection target behavioral, biomedical, and structural risk factors. Some of these prevention strategies have been evaluated in randomized clinical trials (RCTs) with HIV seroincidence endpoints. When RCTs are not feasible, a variety of observational and quasiexperimental research approaches can provide insight as to program effectiveness of specific strategies. Only five RCTs have demonstrated a notable decrease in sexually acquired HIV incidence. These include the Mwanza study of syndromic management of sexually transmitted diseases and three male circumcision trials in East Africa; a microbicide trial reported in 2009 shows substantial promise for the efficacy of PRO 2000 (0.5% gel).

SUMMARY

The combined programmatic and scientific efforts to reduce sexual transmission of HIV have made incremental progress. New prevention tools are needed to stem the continued spread of HIV, though microbicides and vaccines will take many more years to develop, test, and deploy. Combination strategies of existing modalities should be tested to evaluate the potential for more proximate prevention benefits.

Microfinance and HIV/AIDS prevention: assessing its promise and limitations

Researchers increasingly argue that poverty and gender inequality exacerbate the spread of HIV/AIDS and that economic empowerment can therefore assist in the prevention and mitigation of the disease, particularly for women. This paper critically evaluates such claims. First, we examine the promises and limits of integrated HIV/AIDS prevention and microfinance programs by examining the available evidence base. We then propose future research agendas and next steps that may help to clear current ambiguities about the potential for economic programs to contribute to HIV/AIDS risk reduction efforts.

HIV prevalence, risks for HIV infection, and human rights among men who have sex with men (MSM) in Malawi, Namibia, and Botswana

Background

In the generalized epidemics of HIV in southern Sub-Saharan Africa, men who have sex with men have been largely excluded from HIV surveillance and research. Epidemiologic data for MSM in southern Africa are among the sparsest globally, and HIV risk among these men has yet to be characterized in the majority of countries.

Methodology

A cross-sectional anonymous probe of 537 men recruited with non-probability sampling among men who reported ever having had sex with another man in Malawi, Namibia, and Botswana using a structured survey instrument and HIV screening with the OraQuick© rapid test kit.

Principal Findings

The HIV prevalence among those between the ages of 18 and 23 was 8.3% (20/241); 20.0% (42/210) among those 24–29; and 35.7% (30/84) among those older than 30 for an overall prevalence of 17.4% (95% CI 14.4–20.8). In multivariate logistic regressions, being older than 25 (aOR 4.0, 95% CI 2.0–8.0), and not always wearing condoms during sex (aOR 2.6, 95% CI 1.3–4.9) were significantly associated with being HIV-positive. Sexual concurrency was common with 16.6% having ongoing concurrent stable relationships with a man and a woman and 53.7% had both male and female sexual partners in proceeding 6 months. Unprotected anal intercourse was common and the use of petroleum-based lubricants was also common when using condoms. Human rights abuses, including blackmail and denial of housing and health care was prevalent with 42.1% (222/527) reporting at least one abuse.

Conclusions

MSM are a high-risk group for HIV infection and human rights abuses in Malawi, Namibia, and Botswana. Concurrency of sexual partnerships with partners of both genders may play important roles in HIV spread in these populations. Further epidemiologic and evaluative research is needed to assess the contribution of MSM to southern Africa's HIV epidemics and how best to mitigate this. These countries should initiate and adequately fund evidence-based and targeted HIV prevention programs for MSM.

Behavioural strategies to reduce HIV transmission: how to make them work better

This paper makes five key points. First is that the aggregate effect of radical and sustained behavioural changes in a sufficient number of individuals potentially at risk is needed for successful reductions in HIV transmission. Second, combination prevention is essential since HIV prevention is neither simple nor simplistic. Reductions in HIV transmission need widespread and sustained efforts, and a mix of communication channels to disseminate messages to motivate people to engage in a range of options to reduce risk. Third, prevention programmes can do better. The effect of behavioural strategies could be increased by aiming for many goals (eg, delay in onset of first intercourse, reduction in number of sexual partners, increases in condom use, etc) that are achieved by use of multilevel approaches (eg, couples, families, social and sexual networks, institutions, and entire communities) with populations both uninfected and infected with HIV. Fourth, prevention science can do better. Interventions derived from behavioural science have a role in overall HIV-prevention efforts, but they are insufficient when used by themselves to produce substantial and lasting reductions in HIV transmission between individuals or in entire communities. Fifth, we need to get the simple things right. The fundamentals of HIV prevention need to be agreed upon, funded, implemented, measured, and achieved. That, presently, is not the case.