Cofactor infections and HIV epidemics in developing countries: implications for treatment

Elevated levels of inflammatory plasma biomarkers are associated with risk of HIV infection

BACKGROUND

To determine if individuals, from HIV-1 serodiscordant couple cohorts from Rwanda and Zambia, who become HIV-positive have a distinct inflammatory biomarker profile compared to individuals who remain HIV-negative, we compared levels of biomarkers in plasma of HIV-negative individuals who either seroconverted (pre-infection) and became HIV-positive or remained HIV-negative (uninfected).

RESULTS

We observed that individuals in the combined cohort, as well as those in the individual country cohorts, who later became HIV-1 infected had significantly higher baseline levels of multiple inflammatory cytokines/chemokines compared to individuals who remained HIV-negative. Genital inflammation/ulceration or schistosome infections were not associated with this elevated profile. Defined levels of ITAC and IL-7 were significant predictors of later HIV acquisition in ROC predictive analyses, whereas the classical Th1 and Th2 inflammatory cytokines such as IL-12 and interferon-γ or IL-4, IL-5 and Il-13 were not.

CONCLUSIONS

Overall, the data show a significant association between increased plasma biomarkers linked to inflammation and immune activation and HIV acquisition and suggests that pre-existing conditions that increase systemic biomarkers represent a factor for increased risk of HIV infection.

Schistosomiasis is associated with incident HIV transmission and death in Zambia

Background

We examined relationships between schistosome infection, HIV transmission or acquisition, and all-cause death.

Methods

We retrospectively tested baseline sera from a heterosexual HIV-discordant couple cohort in Lusaka, Zambia with follow-up from 1994–2012 in a nested case-control design. Schistosome-specific antibody levels were measured by ELISA. Associations between baseline antibody response to schistosome antigens and incident HIV transmission, acquisition, and all-cause death stratified by gender and HIV status were assessed. In a subset of HIV- women and HIV+ men, we performed immunoblots to evaluate associations between Schistosoma haematobium or Schistosoma mansoni infection history and HIV incidence.

Results

Of 2,145 individuals, 59% had positive baseline schistosome-specific antibody responses. In HIV+ women and men, baseline schistosome-specific antibodies were associated with HIV transmission to partners (adjusted hazard ratio [aHR] = 1.8, p<0.005 and aHR = 1.4, p<0.05, respectively) and death in HIV+ women (aHR = 2.2, p<0.001). In 250 HIV- women, presence of S. haematobium-specific antibodies was associated with increased risk of HIV acquisition (aHR = 1.4, p<0.05).

Conclusion

Schistosome infections were associated with increased transmission of HIV from both sexes, acquisition of HIV in women, and increased progression to death in HIV+ women. Establishing effective prevention and treatment strategies for schistosomiasis, including in urban adults, may reduce HIV incidence and death in HIV+ persons living in endemic areas.

This study explored the association between schistosome infections (a disease caused by parasitic flatworms, also known as ‘snail fever’, which is very common throughout sub-Saharan Africa) and human immunodeficiency virus (HIV). We found in Lusaka, the capital of Zambia, that schistosome infections were associated with transmission of HIV from adult men and women, and schistosome infections were also associated with increased HIV acquisition in adult women. We additionally found that schistosome infections were associated with death in HIV+ adult women. Since treatment of schistosome infections with praziquantel is inexpensive, effective, and safe, schistosomiasis prevention and treatment strategies may be a cost-effective way to reduce not only the symptoms associated with the infection, but also new cases of HIV and death among HIV+ persons. Though often viewed as an infection of predominantly rural areas and children, this study highlights that schistosomiasis prevention and treatment efforts are also needed in urban areas and among adults.

Community-level income inequality and HIV prevalence among persons who inject drugs in Thai Nguyen, Vietnam

Socioeconomic status has a robust positive relationship with several health outcomes at the individual and population levels, but in the case of HIV prevalence, income inequality may be a better predictor than absolute level of income. Most studies showing a relationship between income inequality and HIV have used entire countries as the unit of analysis. In this study, we examine the association between income inequality at the community level and HIV prevalence in a sample of persons who inject drugs (PWID) in a concentrated epidemic setting. We recruited PWID and non-PWID community participants in Thai Nguyen, Vietnam, and administered a cross-sectional questionnaire; PWID were tested for HIV. We used ecologic regression to model HIV burden in our PWID study population on GINI indices of inequality calculated from total reported incomes of non-PWID community members in each commune. We also modeled HIV burden on interaction terms between GINI index and median commune income, and finally used a multi-level model to control for community level inequality and individual level income. HIV burden among PWID was significantly correlated with the commune GINI coefficient (r = 0.53, p = 0.002). HIV burden was also associated with GINI coefficient (β = 0.082, p = 0.008) and with median commune income (β = −0.018, p = 0.023) in ecological regression. In the multi-level model, higher GINI coefficient at the community level was associated with higher odds of individual HIV infection in PWID (OR = 1.46 per 0.01, p = 0.003) while higher personal income was associated with reduced odds of infection (OR = 0.98 per $10, p = 0.022). This study demonstrates a context where income inequality is associated with HIV prevalence at the community level in a concentrated epidemic. It further suggests that community level socioeconomic factors, both contextual and compositional, could be indirect determinants of HIV infection in PWID.

Limits to evidence-based health policymaking: policy hurdles to structural HIV prevention in Tanzania

Despite the well-documented role of highly co-endemic biological cofactors in facilitating HIV transmission and the availability of comparatively inexpensive tools to control them, cofactor-related interventions are only hesitantly included into African HIV prevention strategies. Against this background, this study analyzes political obstacles to policy-uptake of evidence concerning structural HIV prevention. The data used stem from fieldwork conducted in Tanzania between 2007 and 2009. They include 92 in-depth interviews with key AIDS policymakers and observations of 8 national-level policy meetings. Adopting a political economy perspective, the study shows that 1) assuming cost-aversion as a spontaneous reflex of policymakers is empirically wrong and analytically misleading, 2) that political constituencies induce a path dependence of allocative decisions inconducive to structural prevention, 3) that interventions' political attractiveness depends on the nature of their outputs and the expected temporality of political returns, 4) that policy fragmentation entailed by vertical disease control disfavours the consideration of broader causalities, and 5) that cofactor-based measures are hampered by policymakers' perception of structural prevention as being excessively complex and ultimately tantamount to poverty eradication. Confronting the policy players' reading of the Tanzanian situation with recent and classical literature on evidence-based decision-making and the politics of public health, this paper shows that, far from being strictly evidence-driven, HIV prevention policies result from a politically negotiated aggregation of competing, frequently non-optimizing rationalities. A realistic appraisal of policy processes suggests that the failure to consider the invariably political nature of HIV-related policymaking hampers the formulation of effective, politically informed strategies for positive change. Consequently, developing policy practitioners' understanding of how to effectively engage in evidence-influenced political struggles over priorities might be more instrumental in improving HIV prevention strategies than attempts to sidestep these ineradicably antagonistic controversies though technical decision tools meant to optimize health outcomes via the formulation of 'rational consensus'.

Poverty, sex and HIV

There is an ongoing debate about the relative importance of economic factors (notably poverty) and sexual behavior in driving the AIDS epidemic. This paper draws on relevant research and cross-country regression analysis to argue that the impact of economic determinants is dwarfed by contextual factors within Africa. The regression analysis suggests that controlling for per capita income, calories per capita and the ratio of female to male participation rates (none of which were statistically significant): being a Southern African country increases expected HIV prevalence 8.3 times; being in the rest of Sub-Saharan Africa 3 times; being a predominantly Protestant country 2.5 times; and being a predominantly Muslim country reduces expected HIV prevalence to 62% of the base case. Including the share of income going to the poor did not improve the model and was itself statistically insignificant. The analysis suggests that poverty may play a role in the HIV epidemic in some countries (and may well be a factor affecting the vulnerability of some people to HIV infection in all countries) but that its overall impact is dwarfed by social and behavioral factors.