Complexity, cofactors, and the failure of AIDS policy in Africa

The Interaction between HIV and Intestinal Helminth Parasites Coinfection with Nutrition among Adults in KwaZulu-Natal, South Africa

In South Africa few studies have examined the effects of the overlap of HIV and helminth infections on nutritional status. This cross-sectional study investigated the interaction between HIV and intestinal helminths coinfection with nutritional status among KwaZulu-Natal adults. Participants were recruited from a comprehensive primary health care clinic and stratified based on their HIV, stool parasitology, IgE, and IgG4 results into four groups: the uninfected, HIV infected, helminth infected, and HIV-helminth coinfected groups. The nutritional status was assessed using body mass index, 24-hour food recall, micro-, and macronutrient biochemical markers. Univariate and multivariate multinomial probit regression models were used to assess nutritional factors associated with singly and dually infected groups using the uninfected group as a reference category. Biochemically, the HIV-helminth coinfected group was associated with a significantly higher total protein, higher percentage of transferrin saturation, and significantly lower ferritin. There was no significant association between single or dual infections with HIV and helminths with micro- and macronutrient deficiency; however general obesity and low micronutrient intake patterns, which may indicate a general predisposition to micronutrient and protein-energy deficiency, were observed and may need further investigations.

Financing structural interventions: going beyond HIV-only value for money assessments

OBJECTIVE

Structural interventions can reduce HIV vulnerability. However, HIV-specific budgeting, based on HIV-specific outcomes alone, could lead to the undervaluation of investments in such interventions and suboptimal resource allocation. We investigate this hypothesis by examining the consequences of alternative financing approaches.

METHODS

We compare three approaches for deciding whether to finance a structural intervention to keep adolescent girls in school in Malawi. In the first, HIV and non-HIV budget holders participate in a cross-sectoral cost-benefit analysis and fund the intervention if the benefits outweigh the costs. In the second silo approach, each budget holder considers the cost-effectiveness of the intervention in terms of their own objectives and funds the intervention on the basis of their sector-specific thresholds of what is cost-effective or not. In the third cofinancing approach, budget holders use cost-effectiveness analysis to determine how much they would be willing to contribute towards the intervention, provided that other sectors are willing to pay for the remaining costs. In addition, we explore approaches for determining the HIV share in the cofinancing scenario.

RESULTS

We find that efficient structural interventions may be less likely to be prioritized, financed and taken to scale where sectors evaluate their options in isolation. A cofinancing approach minimizes welfare loss and could be incorporated in a sector budgeting perspective.

CONCLUSION

Structural interventions may be underimplemented and their cross-sectoral benefits foregone. Cofinancing provides an opportunity for multiple HIV, health and development objectives to be achieved simultaneously, but will require effective cross-sectoral coordination mechanisms for planning, implementation and financing.

Labor migration, externalities and ethics: theorizing the meso-level determinants of HIV vulnerability

This paper discusses labor migration as an example of how focusing on the meso-level highlights the social processes through which structural factors produce HIV risk. Situating that argument in relation to existing work on economic organization and HIV risk as well as research on labor migration and HIV vulnerabilities, the paper demonstrates how analyzing the processes through which labor migration creates vulnerability can shift attention away from the proximate behavioral determinants of HIV risk and toward the community and policy levels. Further, it presents the concepts of externalities and the ethics of consumption, which underline how both producers and consumers benefit from low-waged migrant labor, and thus are responsible for the externalization of HIV risk characteristic of supply chains that rely on migrant labor. These concepts point to strategies through which researchers and advocates could press the public and private sectors to improve the conditions in which migrants live and work, with implications for HIV as well as other health outcomes.

Living with uncertainty

The persistence of highly endemic parasitic, bacterial and viral diseases makes individuals and populations vulnerable to emerging and re-emerging diseases. Evaluating the role of multiple component, often interacting, causes of disease may be impossible with research tools designed to isolate single causes. Similarly, it may not be possible to identify statistically significant treatment effects, even for interventions known to be effective, when multiple morbidities are present. Evidence continues to accumulate that nutritional deficiencies, bacterial, viral and parasitic coinfections accelerate HIV transmission. Inclusion of antiparasitics and other beneficial interventions in HIV-prevention protocols is impeded by reliance on inappropriate methodologies. Lack of full scientific certainty is not a reason for postponing safe, cost-effective measures to prevent irreversible damage.

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'.

Preliminary report of HIV and Toxoplasma gondii occurrence in pregnant women from Mozambique

Toxoplasmosis, a protozoan disease, causes severe disease in fetuses during pregnancy and deadly encephalitis in HIV patients. There are several studies on its seroprevalence around the world, but studies focusing on African countries are limited in number and mostly anecdotal. We studied two groups of samples from Mozambique by ELISA, using serum samples from 150 pregnant women and six Cerebrospinal fluid (CSF) samples from AIDS patients with encephalitis. HIV status was confirmed, and CD4 blood counts were obtained from HIV-positive pregnant women. IgG seroprevalence of the group as a whole was 18.7% (28/150), with a higher prevalence in HIV-positive individuals compared to those who were HIV-negative (31.3%, [18/58] vs. 10.9%, [10/92]) patients. These data may be biased due to cumulative effects of exposition affecting disease prevalence. If corrected, this data may indicate an interaction of HIV and T. gondii. Prevalence of both diseases increases with age, but this is more clearly seen for toxoplasmosis (p < 0.005) than HIV infection, possibly explained by higher transmission of HIV after childhood. In HIV patients suffering from encephalitis, CSF serology showed that 33% of specific IgG CSF had a high avidity, which was in accordance with the data from the group of pregnant women. Lower prevalence rates of both infections in older groups could be explained by more deaths in the infected groups, resulting in an artificially lower prevalence. Using CD4 counts as a marker of time of HIV infection, and correcting for age, patients with contact with T. gondii had fewer CD4 cells, suggesting prolonged HIV disease or other causes. Toxoplasma IgG prevalence is higher in HIV+ groups, which could be ascribed to HIV- and T. gondii-associated risk factors, such as exposure to higher and more diverse social contacts. The low incidence of Toxoplasma IgG in younger age groups shows that transmission could be related to better access to cyst-containing meat in adulthood, as environmental transmission due to oocysts is usually blamed for higher incidence in children. Taken together, these data support the urgent need of research in toxoplasmosis in Africa, especially in the presence of HIV epidemics.

The relationship between economic evaluations and HIV and AIDS treatment policies

PURPOSE OF REVIEW

Economics, and specifically economic evaluations, are increasingly being utilized to provide treatment policy guidance to decision makers. This article reviews work that has contributed to understanding of the relationship.

RECENT FINDINGS

There is a paucity of research explicitly investigating the association between economic evaluations and HIV and AIDS treatment policy. Where it does exist, it is weak. Factors contributing to the limited impact include lack of reliable and trusted data; absence of local cost-effectiveness data for different interventions; contradictory results; challenges associated with understanding complex economic/mathematical models; inefficient implementation of HIV and AIDS policies; inability to pursue long-term health planning needs; and political will.

SUMMARY

Consideration of the ways in which economic evaluations can have greater influence over HIV and AIDS policies is needed. The weak relationship between the two reflects the complicated and multifaceted decision-making process that is often influenced by socioeconomic and political factors. If an economic evaluation is to influence policy, then cognizance of this is important. Extending the economic toolkit to include broader-based models that incorporate political economy variables, but do not compromise on comprehension, validity and robustness, will offer better informed policy recommendations.

Concurrent sexual partnerships do not explain the HIV epidemics in Africa: a systematic review of the evidence

The notion that concurrent sexual partnerships are especially common in sub-Saharan Africa and explain the region's high HIV prevalence is accepted by many as conventional wisdom. In this paper, we evaluate the quantitative and qualitative evidence offered by the principal proponents of the concurrency hypothesis and analyze the mathematical model they use to establish the plausibility of the hypothesis.We find that research seeking to establish a statistical correlation between concurrency and HIV prevalence either finds no correlation or has important limitations. Furthermore, in order to simulate rapid spread of HIV, mathematical models require unrealistic assumptions about frequency of sexual contact, gender symmetry, levels of concurrency, and per-act transmission rates. Moreover, quantitative evidence cited by proponents of the concurrency hypothesis is unconvincing since they exclude Demographic and Health Surveys and other data showing that concurrency in Africa is low, make broad statements about non-African concurrency based on very few surveys, report data incorrectly, report data from studies that have no information about concurrency as though they supported the hypothesis, report incomparable data and cite unpublished or unavailable studies. Qualitative evidence offered by proponents of the hypothesis is irrelevant since, among other reasons, there is no comparison of Africa with other regions.Promoters of the concurrency hypothesis have failed to establish that concurrency is unusually prevalent in Africa or that the kinds of concurrent partnerships found in Africa produce more rapid spread of HIV than other forms of sexual behaviour. Policy makers should turn attention to drivers of African HIV epidemics that are policy sensitive and for which there is substantial epidemiological evidence.

Treating cofactors can reverse the expansion of a primary disease epidemic

BACKGROUND

Cofactors, "nuisance" conditions or pathogens that affect the spread of a primary disease, are likely to be the norm rather than the exception in disease dynamics. Here we present a "simplest possible" demographic model that incorporates two distinct effects of cofactors: that on the transmission of the primary disease from an infected host bearing the cofactor, and that on the acquisition of the primary disease by an individual that is not infected with the primary disease but carries the cofactor.

METHODS

We constructed and analyzed a four-patch compartment model that accommodates a cofactor. We applied the model to HIV spread in the presence of the causal agent of genital schistosomiasis, Schistosoma hematobium, a pathogen commonly co-occurring with HIV in sub-Saharan Africa.

RESULTS

We found that cofactors can have a range of effects on primary disease dynamics, including shifting the primary disease from non-endemic to endemic, increasing the prevalence of the primary disease, and reversing demographic growth when the host population bears only the primary disease to demographic decline. We show that under parameter values based on the biology of the HIV/S. haematobium system, reduction of the schistosome-bearing subpopulations (e.g. through periodic use of antihelminths) can slow and even reverse the spread of HIV through the host population.

CONCLUSIONS

Typical single-disease models provide estimates of future conditions and guidance for direct intervention efforts relating only to the modeled primary disease. Our results suggest that, in circumstances under which a cofactor affects the disease dynamics, the most effective intervention effort might not be one focused on direct treatment of the primary disease alone. The cofactor model presented here can be used to estimate the impact of the cofactor in a particular disease/cofactor system without requiring the development of a more complicated model which incorporates many other specific aspects of the chosen disease/cofactor pair. Simulation results for the HIV/S. haematobium system have profound implications for disease management in developing areas, in that they provide evidence that in some cases treating cofactors may be the most successful and cost-effective way to slow the spread of primary diseases.